Series

Perfect Dark

4 games, 2000–2010.

Games

Mechanics

Mechanic	Perfect Dark 2000
Autoaim	Crosshair pull
Damage formula	Fixed table
Difficulty level	Table of scales
Locational damage	Hit location
Reaction delay	Sight timer

A marked cell changed from the game before. “Uses” means the game has the mechanic, with no variant recorded yet.

Every claim, by mechanic and game

Concept	Perfect Dark 2000
Autoaim	Perfect Dark's standard autoaim, for a gun whose autoaim is on, scores each character on screen and takes the highest score. It skips teammates, the dead and dying, and anyone not holding a gun (unless flagged `CHRCFLAG_FORCEAUTOAIM`). A candidate needs a clear line from the player, its screen center in the middle half of the screen's width, and its height reaching into the band from 17.5% to 82.5% of the screen's height; the screen's center must lie within 1.5 of its screen widths of its middle, times a solo scale (perfect-dark/autoaim-scale). The score is 1 when the screen's center x lies between the target's left and right screen edges, and otherwise falls off with the gap over that margin. The walk runs from the end of a list `props_sort` orders by `prop->z`, largest first, which the decompilers' comment calls "furthest first"; since a score of 1 ends the walk, the nearest such target wins on that reading. Doom traces ahead and 5.625° to each side for a target, and Duke Nukem 3D's `aim` takes the target within 8.4° of the facing that is nearest along it. Code In solo Perfect Dark the autoaim margin (perfect-dark/autoaim) is multiplied by `g_AutoAimScale`, which `lv_update_solo_handicaps` sets by difficulty: 1.5 on Agent, 0.75 on Special Agent, 0.2 on Perfect Agent, and 1 on the Perfect Dark difficulty; the ntsc-final build takes the non-Japanese values (`g_Jpn` is false). Co-op and Counter-Operative use their own values. Code Perfect Dark's autoaim moves the crosshair, not the view: once a target is picked, `bmove_update_autoaim_x_prop` and `_y_prop` set the aim point to the target's screen center (clamped to the window), and a new target replaces the old only after a 30/60 s hold; `bgun_swivel` then eases the crosshair toward the point, keeping a fraction `crossdamp` of the gap each 1/240 s (a unit the decompilers' comments give). On NTSC that fraction, `autoaimdamp`, falls by 0.00032 a 60th of a second while autoaim holds a target, from at most 0.979 (it climbs back there while none is held) to 0.963, so the pull strengthens over up to 50/60 s (computed); at 0.963 the crosshair closes 14% of the gap each 60th of a second (1 − 0.963⁴, computed). The shot leaves through the crosshair's position plus a random spread. Doom's bullet keeps the player's facing and takes only a vertical slope, and Duke Nukem 3D turns the shot itself to the target's angle in the call that fires it. Code
Damage formula	The Falcon 2's single shot in Perfect Dark carries a damage of 1 (`invfunc_falcon2_singleshot`), read by `gset_get_damage`. A guard adds each hit to its `damage` against a `maxdamage` that `chr_allocate` sets to 4 (a level's AI script can set another), and `chr_react_to_damage` starts its death once `damage` reaches it; so on Perfect Agent a default guard takes 4 Falcon 2 shots to a limb, 2 to the torso, or 1 to the head (computed). The player's health starts at 1, and a hit takes `damage × 0.125` from it, so a guard's Falcon 2 bullet takes an eighth on Perfect Agent (computed). Each Doom pistol bullet deals 5, 10, or 15 against a zombieman's 20. Code
Difficulty level	Solo Perfect Dark scales damage by difficulty in `lv_update_solo_handicaps`, which runs every tick: a guard's hit on the player is multiplied by 0.5 on Agent, 0.6 on Special Agent, and 1 on Perfect Agent (and on the Perfect Dark difficulty, times its own enemy-damage setting); the player's shots are doubled on Agent; and explosions hurt the player 0.25 times on Agent and 0.75 times on Special Agent. On Agent the scales for the damage the player takes, from guards and from explosions, shrink further once health plus shield is at or below 0.6, falling linearly to half at 0.125, so 0.25 for a guard's hit (computed); the player's ×2 on its own shots stays fixed. Doom halves all damage to the player on its easiest skill, `sk_baby`. Code
Locational damage	Perfect Dark's `chr_damage` scales a hit by the body part (`hitpart`) it struck: a head hit is multiplied by 4 and a torso hit doubled, the limbs and pelvis keep the damage, and a hit on the held gun or a hat deals none. Outside normal multiplayer a gun shot fired by a player multiplies a head hit by a further 25 (`headshotdamagescale`), 100 in all, unless a shield took it; a Skedar's head is only doubled, and its tail takes 10 times. A hit with no part (`HITPART_GENERAL`, as when a guard's bullet hits the player) is halved and then doubled as the torso, so it keeps its damage. Doom's `P_LineAttack` passes a bullet's damage to the thing it hits with no body part. Code
Reaction delay	A Perfect Dark combat simulant keeps a `shootdelaytimer60` per target: it resets to 0 when the simulant picks a new target, counts up in 60ths of a second while the target is in sight, and counts back down to 0 while it isn't. Unless a burst or the Cyclone's secondary discharge is already under way (`burstsdone` above 0 or `cyclonedischarging`), which keeps it firing without the test, the simulant opens fire only once the timer reaches its difficulty's `shootdelay60`: 90 (1.5 s) for Meat, 60 for Easy, 30 for Normal, 15 for Hard, and 0 for Perfect and Dark, on NTSC; the target must also be within 45/256 of a turn (63°, computed) of its facing, unless the simulant is dizzy. Doom gives each monster a `reactiontime` at spawn (8 for the zombieman, 0 on Nightmare), counted down once per `A_Chase` call, and refuses a ranged attack until it reaches 0, unless the monster has been hit since it last checked (`MF_JUSTHIT`). Code