All of my changes to Quake's single-player and the rationale behind them are explained below. Each has been carefully weighed and tested, from the points of view of both a player and a mapper. In all cases I preferred a light touch, looking for ways to gain maximum benefit by applying minimal pressure to the design. They don't really change the game, and yet they really do.
Over time, my reasons for changes coalesced around a very clearly motivated "spirit" to Copper, summed up in the form of a list of goals:
- Introduce no new major mechanics; only tweak existing mechanics and their interactions
- Ensure that any changed or adjusted mechanics are clearly legible through gameplay (no invisible fudging of outcomes while hiding causes)
- Fix the "gameplay bugs" we've all just gotten used to since 1996, without sacrificing what value and charm they may have
- Incorporate players' existing expectations and Quake instincts (don't set the player up to feel like their old instincts "betrayed" them)
- Expand, never reduce, opportunity for skill-based play at high levels
- Give level designers more options and flexibility to build compelling gameplay and not just pretty rooms
- Maintain backwards compatibility with Quake's original four episodes and as many custom maps as feasible
Ring Of Shadows
The Ring of Shadows now protects the player in combat: monsters no longer know exactly where the player is once awakened. They will shoot or melee randomly into an invisible player's general area, hoping to get lucky, usually missing, and sometimes even hitting other monsters. In exchange, the Ring no longer makes all monsters deaf to your gunfire. This makes the Ring function much the same as the Invisibility powerup in Doom/Doom II, but with this addition: ranged attacks always miss the player, even if they would hit dead-on by chance. Getting boxed into a corner in melee is as deadly as ever, so players should take advantage of the confusion to stay light on their feet. The protection against ranged attacks does not extend to splash damage from nearby explosions, or leaping melee attacks.
Dogs are known to be able to hunt using an otherworldly power of perception known as "smell" and are unaffected by the Ring of Shadows once awakened. Fiends are affected just like every other monster, because they have eyes. (To be less facetious about it, it's more fun to watch deadly Fiends dive hard into other monsters by mistake, or over cliff edges, than it is to imagine they can 'just sense' you.)
Mappers almost never bother to place a Ring of Shadows in their levels, and when they do, players are never excited to find one, because the power to merely delay engagement with monsters is of very limited value. The improved Ring is now a very good 'soft' powerup for mappers to place in their levels, especially when hidden before nasty ambushes, when granting the extreme power of a Quad or a Pentagram is too much. Players also enjoy watching the chaos that ensues.
Importing Doom-style invisibility also imported the reasons for Doom players' perception of invisibility as a "powerdown." The Ring originally blunted melee damage in Copper, but not ranged attacks. It was expected that monsters' confused random shots would make for adequate ranged protection for invisible players, but it created an upside-down situation. Average-skill players who didn't have exact muscle memory for anticipating and dodging attacks perfectly were hit a lot less and liked it, but the unpredictability robbed high-skill players of the ability to consistently avoid hits, sometimes being tricked into dodging into a projectile that "should" have missed.
Becoming effectively non-solid to projectiles achieves the original intended effect across all skill levels without requiring per-skill mechanical variations, and close quarters being the primary threat dovetails nicely with the Copper philosophy that difficulty levels should vary mostly through number and arrangement of enemies.
Vore missiles have been given a limited turn rate. They will still follow the player aggressively, but sidestepping them is now a skill-based option to buy a few seconds of safety before they loop around again (or to swing them into walls or other targets). Their maneuverability is reduced once their parent Vore has been killed, providing the player another option for shaking them that encourages staying in combat rather than fleeing.
Vanilla Vores are hard for the mapper to use well because the player response to them is almost always excessive caution, leading to a hard stop on combat. The minigame of "Hide From The Voreball" is so high priority because of their perfect homing that it overrides all other gameplay rather than adding to it, and often forces the player to backtrack through lots of empty map. Fighting a Vore in the open is also a time-delayed death sentence rather than a unique challenge. Mappers therefore tend to deploy Vores alone, frequently as nothing more than turrets. Making Vore missiles home tightly but not perfectly gives the mapper more flexibility to challenge players with Vores in more situations, overlapping in new ways with other monsters, making for more fun level design and combat.
The Vore's lack of an idle animation has also been addressed.
Ogres are "semi-Z-aware." An Ogre is now much better at getting grenades near their target, no longer mindlessly firing far over the target's head or at walls beneath them, but without gaining pinpoint in-your-face Z-accuracy, so the player retains some of the expected advantage from large height differences. The Ogre feels more threatening from more angles, but not unfairly so.
The typical Z-aware Ogre implementation makes for Ogres that dead-eye the player unexpectedly from any angle, but vanilla Ogres are of limited utility to the mapper because they have a hard-coded firing arc, requiring that architecture be customized to accomodate them. The Copper approach is simple: average the hard-coded angle and the perfect-solution angle. This yields an Ogre which is much more effective at localizing the "bouncing grenade chaos" to the player's vicinity, but still feels like the old Ogre, so the player's existing instincts for fighting them don't need to be relearned. The mapper can therefore use Ogres more flexibly and with greater confidence.
This is the only kind of Ogre in Copper. Z-accuracy is not a mapper-selectable option on Ogres, to maintain consistency and predictability for the player.
Zombies can be killed by any explosion, not just rocket-strength blasts. Ogre grenades were formerly too weak to do more than knock Zombies down even on a direct hit; they now do extra damage vs. Zombies, enough to gib them. This gives players a few sneaky extra ways to eliminate them by exploiting other monsters.
Zombies still require explosions to kill. The "axe kills downed Zombies" feature from Honey was not adopted. It makes chopping up Zombies a slow chore just to save a rocket, and defuses the tension that comes from encountering Zombies before the player has a way to kill them, which robs the mapper of a whole family of potential designed scenarios.
As a helpful quality-of-life improvement for the player, one hit from the Axe instantly knocks a Zombie over without having to "wear it down" first.
Zombies no longer need to be standing to be gibbed by an explosion. Grenades will still not collide against a downed Zombie and explode (this would lead to too many accidental blasts), but a grenade that comes to rest on or next to one before exploding, or explodes against something else that's close enough, will still reduce a Zombie to chunks. The Rocket Launcher works the same way. To be gibbed by Quad Damage shotgun or nailgun fire, however, Zombies must still be standing.
Monsters no longer get stuck eternally infighting with a Zombie they can't kill. They will attack it until they knock it down, then consider it dead and revert to their previous target. The Zombie will also not resume infighting with that monster when it stands back up.
After a Shambler's first two melee attacks in a row, a chance of making a lightning attack in place of the next melee will gradually build. The "Shambler Dance" of moving in and out to induce but avoid melee attacks remains a viable strategy for a few seconds at a time, but attempting to exploit it continuously is now a more dangerous gamble. Coincidentally, the length of two melee attacks is almost exactly as long as a Shambler can survive sustained fire from the Perforator before dropping.
Players have been heard to complain that once they became skilled at the Dance, Shamblers ceased to be scary. This change still lets players briefly mitigate a Shambler with a practiced series of fake-outs, but infuses the act with a new tension: doing so without an exit plan is as dangerous as it ought to be. Making the strategy less reliable for players makes Shamblers more reliable for mappers: they can now count on a Shambler being a frightening, in-your-face rush monster that forces the player to dance on the move, and not in place.
Shamblers no longer try to fire lightning from beyond the maximum range of their lightning. This bug was largely unnoticeable at the typical scale of Quake's original maps, but became clear as custom Quake levels grew in scope. There is no longer an envelope at the edge of their range within which the charging-up animation is a false signal. (The other potential fix, extending the range of the lightning instead, was rejected out of a desire not to muddy the role of a Shambler as a frightening, in-your-face rush monster with what would amount to the power to snipe the player at a distance.)
The Shambler's lightning bolt texture has been fixed to match Quake's other lightning assets.
Enforcers, rather than firing twice in a salvo, begin firing continuously like a turret until they lose line of sight or are interrupted by pain. When encountered in groups or at range, it places greater emphasis on using movement, pain-juggling, and selectively breaking line of sight to manage their threat, which helps all Enforcers feel less like speed bumps and more like a unique threat. To avoid unbalancing the game too excessively in their presence, their laser bolt damage has been reduced from 15 each to 12.
Enforcers have long and likely pain animations, and most only live long enough to fire twice anyway, so this doesn't introduce inordinate difficulty to most maps. It does add one more axis of micro-decisionmaking for players when an Enforcer is on the field, which is one more tool for designers to use to craft gameplay. It also helps differentiate the Enforcer into a more unique role than "better Grunt" or "non-flying Scrag" for both parties. There is an opening in Quake's menagerie for (to borrow more parlance from Doom2) a Chaingunner/Arachnotron-style enemy, and the Enforcer's lack of a strong role and existing style of attack makes them an ideal fit.
The bug where players could be instantly killed by a Fiend, Spawn, or Dog landing on their head has been fixed. Fiends also have a better sense of when their leap path is clear, and will no longer bounce spastically back and forth across a doorway or at the bottoms of stairs.
Knights have had their health reduced from 75 to 72, enough to make it possible to kill them with three careful and complete shotgun blasts instead of always requiring a fourth.
A Hell Knight's magic spreadfire projectiles have been sped up from 300 to 425. This helps make them less of a spammy non-entity at medium to long ranges, while not making the projectile too fast to outrun at close range or dodge at middle range.
Fixes for the various problems with Rotfish (double kill count, being solid too long after death, shrunken head in death frames, getting stuck at the surface of the water) have all been included. They also swim just a little faster and bite just a little harder, so they're not just fodder.
A Spawn that loses sight of its enemy will, eventually, stop leaping around, giving the player another chance to find and kill it in its sluggish state. This mostly preserves the fun-panic unpredictability of Spawns without them being a never-ending crap shoot, making it easier for the mapper to predict how much health or ammo a player might expend fighting them. This behavior interacts with the Ring of Shadows.
Ch'thon still leads his shots to a degree modulated by skill, a necessary component of his balance when there's only so much that can be done with the level around him. His projectiles now travel faster for each time he's been zapped, to add increasing danger and mounting tension to Ch'thon encounters. The hissing bomb-in-flight sound they now make as they narrowly miss the player is pretty good for that, too.
All monsters (except Grunts) already refuse to infight with other monsters of the same classname, but they now take half damage from attacks by such monsters as well. Vores and Ogres are immune to their own splash damage (but not others'), so they can no longer slowly bomb themselves to death.
Infighting monsters who fail to successfully damage their target for 15 seconds will give up on the infight and revert to their previous enemy, so Ogres on plinths no longer accumulate permanent fan clubs milling around their feet. Monsters who do not have a ranged attack will give up after 10 seconds.
Some monsters' bounding boxes have been shortened vertically, so you can't shoot them by firing into empty space above their heads. This does not fix 64x64 monsters getting stuck in rooms with ceilings lower than the height of a Shambler, which requires engine and .bsp support.
Monster behavior in Copper is consistent across all four skill levels, and attack frequency is no longer used to artifically inflate the difficulty of Nightmare skill. Nightmare is now distinguished from Hard by reducing the player's maximum health from 100 to 50. This simulates the way that players lean forward and begin playing for keeps only when their health is unusually low, requiring the player to stay in low-health clutch mode to survive. Easy, Medium, and Hard skill levels are still distinguished from each other by the level design.
The highest difficulty level in the game should reward system mastery and high-level play. Monsters in vanilla Nightmare are aggressive to the point of becoming exploitably broken, forced to stand in place and fire continuously when the player is in sight like mindless turrets. This robs the game of an important source of unpredictability, that of monster movements and actions, which in turn only encourages degenerate cheesy tactics from players that aren't valid on any other skill level, so it has been eliminated.
Very few things in Quake's game code (or, for that matter, Doom's) changed with skill level, and this style of design has been scrupulously maintained. The only things that should vary between skill levels are things which are readily apparent and instantly understood. If a map has more monsters and fewer health items, the player understands the harder situation at a glance. If instead the monsters have more health and the health items give less, the difficulty is increased in an opaque and hidden way, because the player's learned expectations are now wrong. Thus instincts developed on Normal would be useless or even detrimental when trying a map on Hard or Nightmare, and vice versa. Since lowered max health is clearly reflected on the HUD, it is immediately understood by the player and instantly teaches them that playing differently is necessary.
The additional Nightmare-only exceptions that make Voreballs 40% faster and Shambler lightning last for 33% longer (and thus do an extra 10 damage) were found to be unnecessary to the new Nightmare gameplay and have been removed. Skill and muscle memory developed on other difficulties for reacting to Shamblers and Vores will serve the player equally well on Nightmare, and are all the more valuable for it. Grunts and Ogres have a diminishing chance to fire more than once in a row in Nightmare mode to make charging them for quick shutdown kills more risky, but all other monsters behave just like they do on other difficulties.
Version 1.1 added a great deal of polish and features aimed at improving Coop gameplay for players and expanding possibilities for mappers interested in supporting Coop mode. The main goal was to reintroduce fear of death, a constant in singleplayer but entirely absent from Coop. With no real way to lose, owing to players always being able to respawn and keep going no matter what, vanilla Coop is a hectic but tension-free shooting gallery.
A level is now considered failed in Cooperative mode if all players are dead at the same time. Killed players can only respawn as long as there is at least one player currently alive. If the last player dies before anyone has had a chance to respawn, the level resets and must be reattempted from the start. (Singleplayer works this way too, in a manner of speaking, just with a maximum player count of one.) Since this circumstance is vanishingly rare even in a two-player game, a player is now prevented from respawing for five seconds after dying. If another player dies in that window, the cutoff is pushed back a little more, and so on, accelerating the possibility of a Total Party Kill. Death is now dangerous.
Furthermore, unless the level has reset after wiping out, respawned players don't come back with all the ammo and armor they entered the level with. They retain their weapons (since there's no guarantee a level or episode will continue to provide duplicates), but otherwise return to play with nothing to their name but the typical 25 shells. They can have their ammo back, of course - if they can return to the backpack they dropped. Falling into lava or a void thus has the potential to waste vital resources. If this might make finishing the level impossible, players can always try, and start over if they fail - this outcome at least gets them playing again right away rather than degrading to a war of attrition with axes.
Other players are now prevented from snagging each other's backpacks, to prevent accidental deprivation or intentional malice. These player-owned backpacks do not expire and vanish after 2 minutes.
Rather than weapons hovering non-solidly and refusing to interact with any player who already has one, weapons can always be picked up, and will vanish as soon as they do, as in singleplayer. To prevent other players from missing out on having the weapon, Copper considers the party as a whole to have acquired it, and it is immediately granted (along with its ammo) to all players. Finding a secret Lightning Gun when you've already got one should at least be worth some cells, after all.
One more item has seen a party-friendly modification: when a player picks up a Megahealth, in addition to receiving +100 overhealing, all their teammates are restored to full health. (Saving a Megahealth for a well-timed moment in the midst of a tough fight can save the day.)
All of the above changes are siloed to 'coop 1'. The instant and well-supplied respawns and weapons-stay behavior of vanilla are still available as 'coop 2' if you miss that kind of thing.
All changes that follow are universal upgrades to both Cooperative modes.
The frag count displayed on the HUD in Coop now sensibly shows monster kills instead of player kills. Teammate kills, suicides and self-owns like visiting the volcano god are worth -5. Friendly fire can also now be disabled in Coop entirely by setting the 'teamplay' cvar to 1.
There is no longer need for players to be delicate around teleporters and spawnpoints out of fear of someone being telefragged. If the sudden appearance of a player would gib another, that player is safely pushed off the destination instead. The teleporting or respawning player appears as soon as the destination is clear. If the other player is prevented from being pushed away by something, or is being intentionally cheeky, the waiting player can avoid being trapped in teleport limbo by pressing jump or fire to force a telefrag.
This fixes the unfortunate side effect of two players falling into a void at the same time telefragging each other when they're teleported back to solid ground. Sorry about that.
Monsters' attention spans are now wide enough to include multiple players, or rather, they no longer make rigid distinctions about which player they're angry with. They will no longer single-mindedly ignore an easy target just because the last player who harmed them is playing hard-to-get. Get too close, or get in their way, and expect to become their new target without pulling the trigger. While aggro can still be drawn, it's not so easily exploited, so no matter what your buddies are up to, you aren't safe from any monster that can see you. This does mean that a Ring of Shadows is a great way to let your allies take more than their share of the heat. (Announcing your presence with the glowing power of a Quad Damage has an effect, too...)
Monsters will still fixate, for a little while, on any player who hurts them badly enough to trigger a pain animation, something experienced Quake players already have muscle-memory for on a monster-by-monster basis. This adds a dimension of battlefield control to Coop that isn't present in singleplayer, making monsters that are easy to stun (like Ogres) easy to manipulate, and monsters which don't stun so easily (Shamblers) more bullish.
A change of enemy is never random. Choice of player to attack is based solely on a simple assessment of range, forwardness-vs-behindness, and visibility. This makes it easy to develop a 'feel' for when you'll pull a monster's attention and how you can lose it, allowing players to make informed split-second decisions with intent to control a fight, rather than only reacting to the unpredictable.
The dreaded func_plat elevator, which begins rising as soon as anyone steps onto it, works fine with one player but is almost guaranteed to split multiple players apart unless they time their movements very carefully. Now, when a player steps onto a plat, it will automatically check a narrow radius for other players who might be about to hop on, and delay movement for about a second to give anyone it finds a chance. Otherwise, it behaves normally.
The 'timelimit' cvar now has a Coop function. If set, once any player exits the level, the intermission won't be triggered for that many seconds, allowing other players to finish grabbing supplies or anything else they might be doing. Everyone who exits before then still gets to peer through the intermission cameras, and can even pan them around.
Some health pickups have been given a visual pass. By popular request, +15s are now a little smaller than +25s, to more clearly distinguish them. Megahealths now look a little more ornate (only a little - they're still adorably cubic) and have a unique top texture, so they're no longer generic brown boxes when viewed from above.
While this is a break with the "canon" that +15s are rotten +25s, and thus should look similar, too many players seemed unable to tell the existing pickups apart even with extra rot smeared on.
One-point-per-second health degradation when overhealed is now something that simply always happens to every player's health (above 100, or 50 on Nightmare), and is no longer tied to recent Megahealth pickups. Grabbing two Megahealths no longer leads to your health ticking down at twice the rate, and should anyone venture into Copper multiplayer, their health will no longer stop rotting if someone else picks up the same Megahealth after it respawns.
The 50 HP 'safety buffer' that players are healed up to if they finished a prior map with low health is disabled on Nightmare.
The percentage of damage diverted to armor is now proportional to the number of armor HP the player has, rather than always being inherited from the last armor picked up, but otherwise closely matches the original protection amounts players are accustomed to. For example, Red Armor still absorbs the lion's share of damage at first, but effectively 'degrades' to Yellow and then Green protection as it's shot away. The HUD icon still changes color to indicate protection strength, just like before.
This alleviates the effect of a Green Armor lasting longer than a Red Armor, as well as the sudden spike in health damage the player takes after the last points of a Red Armor are lost and the player is left suddenly naked. This also simplifies away the player's awkward mental calculation of deciding whether or not to pick up an armor item when it would raise their armor quantity but lower their armor strength.
The only interaction a player has with an item is to pick it up, so the only decision an item introduces to the game is when to do so. The complex secret armor pickup math of vanilla Quake doesn't make that decision more compelling or interesting, just more opaque. Since the value of an armor pickup is now proportional only to its quantity, more is now unquestionably more, and the only deciding factor is how many points would go to waste. This also helps the mapper predict and adjust difficulty, because every armor granted to the player will wear down and reduce its protection in the same way, while retaining the relatively higher values of Yellow and Red Armor.
'armorvalue'/'armortype' keyvalue hacks still work as normal on monsters.
Armor is now shielded by the Pentagram of Protection, just like health. While the old behavior of still losing armor while invulnerable was something that players were probably used to (those who noticed, at least), it never quite fit the concept of invulnerability, and may very well have simply been a bug. The stylish 666 on the HUD also prevented the player from even knowing how much armor they were losing until the Pent had expired, so this removes the mystery.
The bug where monsters in death animations act as solid walls to bullets and projectiles has been fixed. Shotguns now feel much more effective at crowd control, especially against large amounts of weak monsters. As individual shotgun pellets add their damage to a target, once enough damage to kill it has been totaled up, further pellets will do 50% damage to that target and continue their trace beyond it at full damage. This works similarly to the Doom shotguns, giving Quake's shotguns the same satisfying feeling of room-clearing penetration, while retaining (albeit reducing) the chance of Quake's trademark shotgun-gibbing. Now, on average, it pays off for the player to maneuver to line up targets in rows when shotgunning, and to use the SSG on crowds.
This plays very nice with a Quad Damage.
Nails no longer 'plink' against dying monsters, and grenades do not bounce off of them, passing through instead. Dying monsters are still solid to players and other monsters until the same times in the animations as before.
To help distinguish the two nailguns from each other, so that the Perforator is less of a straight upgrade, the velocity of nails from the Nailgun has been doubled, while the Perforator has been given a little spread (comparable to the Shotgun). This makes the Nailgun better at long-range needling (to reduce the necessity of efficient-but-boring shotgun sniping), while the Perforator is just as good as always at close DPS but potentially wasteful at range. Their damage outputs are unchanged.
The Perforator now fires two regular nails at once, rather than one nail that is "better", to better leverage the aforementioned shoot-through. When the player uses the Perforator with a Quad, the two spikes' damages are always combined against one target, to ensure there is no reduction in ludicrous gibs compared to vanilla Quake.
Lightning from the Thunderbolt will now arc through the player's target to further monsters behind it, dealing diminishing damage to each additional enemy. This helps it cut through crowds in a way the Perforator cannot, while rewarding smart positioning. The lightning will be drawn to targets a little to either side, so while maneuvering to line up enemies is beneficial, it doesn't require railgun-level precision. Rather than watering your rosebush, use the same technique as trimming your hedges.
The top weapon slot, by custom and tradition, is reserved for the most powerful and impressive implement. The vanilla Lightning Gun sure does deplete hit points, but is effectively just a more super supernailgun. This author has chosen to interpret the old-as-QTest tales that id once planned to include a Chain Lightning Gun in the final game by making the Thunderbolt a railgun-adjacent expression of this, to help the eldritch bugzapper rival the BFG9000 for cachet.
Taking the Thunderbolt into the bath is still not recommended.
Players no longer alert monsters by swinging the axe without hitting anything.
The axe view model has been reanimated at 20fps. This makes the axe feel a lot more responsive and satisfying, as the damage frame now lags less behind the attack impulse. Axe damage has also been raised slightly (from 20 to 24), so that it takes exactly as many hits from the Axe to kill any given monster as it takes complete hits from the Shotgun.
The axe now makes sounds when hitting monsters or damageable brushmodels.
Ogre ammo drops have been reduced to 1 rocket each (from 2). Vanilla Ogres were 'ammo neutral' in that it took two grenades (or two grenades worth of shotgun or nail damage) to kill them, and two grenades were dropped in return, so each Ogre was effectively a means of converting other ammo into rockets. The level designer could not then give the player a grenade launcher or rocket launcher without making them instantly overpowered thanks to all the rockets they'd saved up, due to what a bread and butter monster the Ogre is. This change improves the mapper's ability to make rockets rare if they choose, without having to so severely limit use of Ogres.
Enforcer ammo drops are even worse in this regard. This common, low-level enemy drops enough ammo (for the game's most powerful weapon, no less) to kill two more Enforcers. This leads to the severe mapper dilemma that cells cannot be rare (and thus the Thunderbolt cannot be special) if Enforcers are common. For this reason, Copper eliminates Enforcer ammo drops entirely.
The Ogre and the Grenade Launcher have a great deal of overlap on the power curve, so Ogre drops were kept non-zero out of concern over harming the balance of far too many existing levels. Enforcers and the Thunderbolt are far enough apart, and overlap rarely enough in custom maps, that there was no reason for half measures. The number of existing levels that are harmed by this change is very small, and it was considered more than worth it for the sake of the potential number of future maps that will benefit from freer use of a great monster and a great weapon.
Small and large rocket ammo pickups have been reduced to 4 and 8 (from 5 and 10) to give the mapper slightly finer control over the quantity of rockets they dish out. This doesn't actually seem to affect the balance of most existing maps too badly, because a perception that rockets are more rare causes players to maximize their value by using them more on groups and big bads, rather than casually spamming grenades around corners or using the rocket launcher to frag one Knight at a time. The CanDamage() bugfix has also been applied, making explosions less likely to skip targets within their blast radius, so rockets and grenades should compensate in application by feeling a bit more powerful against groups.
All small ammo pickups are now centered on their bounding boxes. The rocket ammo pickups have been redone to match the scale and style of the other ammo boxes, and no longer depict weird fat & skinny rockets.
Monsters now take damage from immersion in lava or slime. They can wade in it without issue, but if they should get in "over their heads" in a place they can't get out of, they won't run around hidden under the surface forever. Monsters pre-placed in lava or slime remain immune to both so as to not break backwards compatibility with existing maps that hide them there on purpose, but they lose their immunity once they fully leave the liquid. Zombies and Scrags are always immune to slime; Zombies because you can't poison the dead, and Scrags because they spit slime and there's no good way to stop them flying into it anyway. Zombies which take damage from lava are gibbed, because that's the only damage that's meaningful.
The bug that caused drowning damage to be partially subtracted from armor has been fixed. The speed at which drowning damage escalates has been cut back a little instead, so that water is still only proportionately as deadly as before. It's about making the player panic so they drown themselves, after all.
The player recovers most of the damage they took from drowning once they're above water again (or if they find themselves a biosuit while drowning). Short choking episodes do no permanent damage, but the longer the player goes without air, the more health is lost permanently. If they dive below the surface before the recovery is complete (in other words, before they get their wind back) the onset of drowning damage comes sooner and harder the next time. This makes players feel a bit more free to explore underwater just a little too long for only short-term risk but no permanent penalty, which should in turn help mappers feel more comfortable with use of swimming gameplay (especially to make the player feel uncomfortable ...).
Drowning damage and recovery (and only those two things) are reduced by half on Nightmare, to stay in proportion with the player's maximum health. Otherwise, shortening the drowning timer so severely may make long underwater segments in some maps not just more scary and deadly, but physically impossible to complete.
A biosuit's protection against lava reduces the player's effective depth in lava by one step (ie if immersed in lava, damage is taken as if chest-deep, and so on). This makes a biosuit effectively proof against lava that is only ankle deep.
The +moveup key is no longer a secret way to swim to the surface faster than holding +jump. The jump key now propels you upward at the same rate as +moveup when underwater. (Looking straight up and swimming forward is still faster than either thanks to engine-based physics quirks, placing such a fix beyond the scope of this mod.) This has no effect on the height of the edge players can use to climb out of a pool.
Keys & Runes
Players can carry more than one key of the same type, should they happen across any. Quake reminds players how many they have with an upper-right-corner print when they grab or use one, and the icon only disappears from the HUD once the last key has been used.
This opens up a family of nonlinear level layout possibilities that use duplicate keys to grant the player some choice in which progression gates to unlock in what order, or to promote certain other gating mechanisms to a higher 'tier' than buttons, without the awkwardness of players being unable to pick up a key when they already have one.
This required a change to how keys work in cooperative play. Keys now disappear when picked up in coop just like in single-player, meaning whichever player grabbed it is the one who has to open the door with it. If that player dies or disconnects, held keys are automatically transferred to a different living player to ensure a map is never made impossible to finish by "losing" a key in an unreachable place. If all other players are dead when a keyholder dies in 'coop 2', that player simply respawns with their keys.
Preach's fix for the "restarting after dying loses your runes" bug has been gratefully incorporated. Players can now safely hero it through all the haunted lands of Quake without resorting to quicksaving if they so desire.
The explobox recursion crash fix has been applied, so barrels-o-fun style usage is possible. Explobox solidity type has been changed to BSP, so the small explobox no longer has a strange tall bounding box, and players can stand and jump up and down on top of both small and large exploboxes (including suicidally barrel-jumping off the tops of them and not just the sides).
Splash damage indirectly activating shootable doors and buttons has been curtailed. Splash radius is reduced by two thirds vs damageable brush entities, so explosions must happen closely enough to be intentional. This preserves the player's ability to use rockets and grenades to activate such entities (and thus the mapper's ability to use them that way), while preventing players or monsters with splash weapons from doing so accidentally.
The flying teleport ball from the final Shub level has custom movement code rather than using
func_train functionality, so while it moves the same as it used to, it can no longer cause the onerous
MOVETYPE_PUSH crash if you touch it wrong.
Intermission cameras will slowly cycle automatically, or can be cycled by players, to ogle every view of the nice level art they didn't notice while deep in skill-based high-level play. Since whichever of 'Jump' or 'Fire' is rebound to cycle the cameras is guaranteed to annoy the 50% of players who use that button, and never the other button, to exit the intermission, intermission cameras in Copper are instead cycled using Impulse 10 & 12 (the next weapon/previous weapon impulses), which most players will likely have bound to the mousewheel.