Void

Void is a single-level PWAD by Mike Watson (Cyb). It uses the music tracks "It's Night Forever" by DipA for the title screen, introduction scene, and victory screen, and "Exquisite" by Andreas Viklund of TSEC through the playable part.

Void was originally released on September 15, 2003 and designed for ZDoom v2.0.48. An update appeared August 12, 2005, designed for v2.0.96.

In his /newstuff review, TheUltimateDoomer praised the atmosphere created by the music, textures, and architecture. Noting a few flaws in gameplay and that puzzle-heavy maps weren't for everyone, he nonetheless concluded, "you've gotta check this out as it's definitely the strangest release of the year and one that you won't forget." As the years pass, Void continues to be regarded as one of the best ever ZDoom mods.

Story
The UAC is performing gateway experiments again. They accidentally teleport a cyberdemon into the lab, but before the cyberdemon can kill the player and a scientist at the console, the entire scene is frozen by a heresiarch. It then proceeds to send all of the marines (both dead and alive) and the cyberdemon into a mysterious and rather surreal dimension. The level finally starts with the player falling a long way down and taking falling damage.

Overview
Void is notorious for its heavy emphasis on jumping and avoiding traps. The level is difficult to complete without saving.

The afrit, dark bishop, reiver, and heresiarch, all enemies from Hexen, make appearances in this wad. There are also some new enemies: the dark imp (which essentially behaves like the undead warrior from Heretic, having two separate projectile attacks) and also spiders. The fist is much more powerful than Doom's normal fist; in fact it is the Hexen fighter's spiked gauntlets weapon combined with the Doom graphics. The unmaker, a weapon mentioned in the Doom Bible and Doom 64, makes an appearance here. The weapon works like a rocket launcher or Heretic's Phoenix Rod, except that the projectiles are invisible. It shoots demon hearts which cause large impact damage with a moderate splash radius. Ammo for the unmaker comes from slain demons.

Essentials
The bulk of Void, after the (skippable) introduction, takes place in a chessboard-themed land of puzzles. The objective is to gather three skull keys to open the way to the lair of the Heresiarch and defeat it. There are several platforming sections, in which falling often means game over; in particular falling into the sky causes you to switch to an external camera and watch your character drifting away in the endless void. Save often!

The avant-garde design of this map masks its linearity. All reachable rooms must be entered, and with few exceptions all scripts must be triggered in a specific order. Even detouring for supplies is rare (the secrets are optional, but skipping the first two would be masochistic).

The augmented punch attack should be used regularly to conserve ammo for boss fights. Depending on the version of ZDoom, same-species infighting may be on by default, which also helps.

Red key
You start the game wounded and with black and white imps moving to intercept you. Dispatch them. You can punch to conserve ammo, given the fist attack has been strengthened. To the east is a rotating tube behind which you can see three barred metal frames. To the west is a sunken room with damaged flooring and a closed exit door. To the north is a portal, currently closed. To the south are wooden doors, open them. You'll find a shotgun and some more chessboard imps. Continue through another doorway to arrive in a room decorated with marble demon faces. There is a switch embedded in the demon face on the northern wall; after hitting it you will see a short cutscene showing the first frame beyond the tube opening up, then you have to deal with two afrits who just awakened. Go to the tube and run through the first frame.

You arrive in a library. At the end of the room, another afrit awaits you. There is a simple switch puzzle: in a wall near the mirrors is an iron mask switch, using it reveals another switch nearby, which reveals a third, then a fourth. The fourth teleports you atop the marble cube in the demon face room. From your elevated position, jump to the ledge in front of you, marked with a red triangle on its floor. (If you miss the jump and fall, you'll have to go to back to the library switch to get back up.) This lowers the demon face in front of you and reveals three afrits.

You enter then the upside-down cloister, the first section with difficult platforming. The cloister forms an upside-down T shape. The north branch goes back to the demon face room, the east is the altar room, and the west is the courtyard. Go to the courtyard and jump across its treacherous obstacles. On the other end, you will find a dark bishop awaiting you in a well on the ceiling (or rather, the upside-down floor). After you kill it, the red skull key will fall from the same well, and a couple of afrits will wake up.

Navigate to the altar room where two more bishops await you, and after another treacherous crossing, you can activate a switch. Watch the giant demon skull move into position and your red skull get placed on the altar. After that, you see the second frame beyond the tube open up. As you go back to the tube, you will notice the demon face room is now flooded by bloodfalls.

Blue key
Crossing the second frame teleports you back to the library, but the ceiling has raised itself and you are now on an upper alcove, overlooking the lower area where the first frame sent you. Turn immediately back to explore the bookshelves to the east; you will find a dark bishop guarding a switch. Activating the switch lowers the bars of the portal in the start room, but also makes the bookshelves lurch around trying to squish you. Hurry out of this trap, jump down to the lower floor, and leave the library through the switch again. Then go to the start room and cross the portal.

You arrive in a colorless area guarded by two bishops. Moving past them, you have your first encounter with dark imps. After climbing a cliff, you find a chaingun and are lowered into a room where you will find a survivor of the UAC lab. After a short conversation, activate the switch to the north, and jump on the moving pillars. Three dark bishops will try to distract you, and you can visit their niches for some health and ammo. Work your way northwest to reach a corridor, but beware: it is full of instant-death traps. At the end of the trapped corridor, you can see an arena through a small window. Hop through the window to be transported to the arena's floor, which triggers a cutscene with the cyberdemon from the introduction falling from the sky. Once free to move, you can pick up a soul sphere and a plasma rifle in the arena, and after you defeat the cyberdemon, four floating lights will appear, indicating an invisible platform allowing you to jump to the blue skull key. Picking it up will teleport you back to the trapped corridor.

As you return to the survivor, a bad surprise awaits you: a reiver teleports right in your buddy's back and kills him. Dispatch the undead and use the blue skull to activate the south wall, which revolves and moves toward you, allowing access to a portal that leads back to the start room. Some new imps are spawned to welcome you back. Move to the tube, then the library, and then the upside-down cloister again to bring your blue skull to the altar. The third teleport frame beyond the tube opens up.

Yellow key
Cross the last frame beyond the tube. Once again, the library's ceiling has elevated to reveal another ledge, on which you now appear, as well as several monsters right behind you. Cross the portal on the western wall. You arrive in a small room with the yellow skull key right behind bars. You can't reach it, but you can step on a contraption to the south of the room. As you do so, you watch a cutscene showing your character being shrunk to the size of a mouse. Take advantage of your tiny size to explore the mouse hole nearby. You will meet your first spider. Beware, they attack like barons do, throwing green balls of fire at you. Climb the cliff, cross a platforming section, and defeat another spider, which will finally allow you to reach the yellow skull. However, it is too big to pick up. Notice the iron mask switch, and the tiny ledge leading to a small passage between the switch and the northern wall. Go through this passage, and you will see a box at the back of the switch. Use the box to remove its cover and you'll notice it is missing a cog; this is why the switch doesn't work. Explore the passage to the east. After an intense fight against several spiders, then against the spider queen, you are rewarded with a cog. Enter the green particle fountain to teleport back up to the switch box, place the cog, navigate to the front of the switch, use it, and the bars will lower. Jump down, climb back on the size change platform, become normal-sized again, and pick up the yellow skull. Go through the portal to return to the library. To jump down to the lowest floor of the library without taking falling damage, you can first jump to a metal column just below the opening. Use the switch as before to get back to the demon face room and navigate to the altar to place your last skull key on it. The unmaker appears! Pick it up, and two demons immediately appear to demonstrate that they drop "demon hearts" which are used as ammo for the unmaker. The marble cube in the demon face room has also been lowered.

Evil marine
A teleporter platform appeared on the lowered demon cube. Go there and step on it. You arrive in a red and white checkerboard room where red and white checkerboard demons wait dormant. They awaken when you activate the switch in the middle of the room, but this also deprives you of your weapons! Punch all the demons to get a new wave, and after the new wave is also dispatched, the east door opens to a room where all your lost weapons await you. Pick up all the demon hearts and then go grab your weapons back. Of course, it is an ambush and you get attacked by a flock of cacodemons and two barons.

There are two puzzle rooms, on the north and on the south. The puzzles are not especially complex. In the north room, step on sky tiles to get them to imitate the pattern which surrounds the tiles. If you mess up, a switch next to the door resets it. Successfully completing the puzzle opens niches full of reivers, each niche containing a switch you have to activate. In the south room, you need to make the switches on the wall match the pattern on the floor, each switch being togglable as often as needed. Solving this simple puzzle spawns a bunch of reivers and raises a small pyramid. Once both rooms are solved, an additional room is accessible on the eastern wall, in which an evil clone of yourself awaits you. Functionally, this clone is Zedek. Although his attacks make the super shotgun sound, they are (invisible) projectiles, not hitscans, so they can be dodged if you are quick enough. After his demise, a pillar of water rises. Climb on it and you'll be thrown back to the start room (falling damage included, so be sure to collect health pickups first).

Heresiarch's lair
The exit portal on the west is now open. Cross it to be teleported to a foggy cliff. Climb down carefully by always looking below you to seek the nearest platform; this will also allow you to pick up health and ammo as you go. Once you reach the bottom, you can restock a bit and open a doorway to the final arena. After activating the switch and defeating eight imps, you face off against the heresiarch. Beware its invulnerability spell (violet circling orbs), which not only prevents damage but reflects projectiles. More monsters, ammo, and health are regularly spawned, so the fight can last for a long time but a player with good footwork should eventually overcome the boss. The death of the heresiarch opens the real exit to the south.

Secrets

 * 1) After coming back from having placed the second skull key on the altar, one of the demon face walls will lower in the marble cube room, revealing an arch-vile. The arch-vile's niche counts as a secret, and contains some ammunition and a medikit. (sector 276)
 * 2) After defeating the evil player clone, a Hexen-style iron mask switch will rise in the starting room with the chessboard imps, behind the center north metal pillar. Activating it teleports you to a ledge overlooking the exit of the first area, where you will find a megasphere. (sector 96)
 * 3) The third secret is found in the foggy cliff area. As you climb down by falling from ledge to ledge, be on the lookout for a platform holding a blur artifact. If you examine carefully your surroundings after each "step" down, it should be easy to find; however there are no routes back up the cliff, so if you miss it the first time, it is gone. (thing 548, ZDoom's "secret trigger" actor)

Bugs
The cyberdemon at the blue key sometimes fires before the entrance cutscene finishes. This means certain death for the player, who cannot move.

When teleporting back to the start point from the blue key, one of the eight imps may fail to spawn.

The 2005 rerelease fixes these issues:
 * Dark imps make no sounds.
 * Sloped sectors on the blue key portal can become too tall to jump over, trapping the player in the crusher hallway.
 * The opening cutscene may "desync" and fail to complete, depending on the application version used.

Speedrunning
Despite the map's popularity, very few demos are known to exist. This is plausibly due to the difficulty noted above; as Cyb himself remarked, "I wasn't expecting any demos of this map given how easy it is to make a tiny error and die in many spots."

Routes and tricks
In a max run, the Compet-n rule of killing monsters at least once is apparently generalized to include deterministic scripted spawns, but not random spawns. Therefore, only the heresiarch and the imps must be killed in the final room, despite it being possible to get 100% by carefully targeting summoned enemies first (which is recommended to some extent anyway, to keep the room from filling with stray projectiles).

Current records
The records for the map at the Doomed Speed Demos Archive are:

Last updated on September 30, 2017.

Deathmatch
Void was not designed for multiplayer modes. It can be played that way only by adding the required additional start points.

Things
This level contains the following numbers of things per skill level:

Note that certain scripted spawns occur even before the introductory cutscene, so the smallest total monster count observed during play is 69, not 38.

Technical information
Custom things are mapped as follows:
 * 20000: bishop statue
 * 20001: dummy blue skullkey
 * 20002: dummy red skullkey
 * 20003: dummy yellow skullkey
 * 20004: bridge light
 * 20005: giant dummy yellow skullkey
 * 20006: demon heart pickup
 * arachnotron: spider
 * spiderdemon: queen spider
 * Phoenix Rod: unmaker
 * undead warrior: dark imp
 * Zedek: evil player clone

Non-Doom things, including enemies, are spawned rather than being placed in the map from the beginning, mostly by script 100. Regardless of skill settings, the scripts will create one Heresiarch, 10 "FireDemon" (afrits), 6 "BishopStatue", 9 "Bishop" (dark bishops), 14 "Knight" (undead warriors), 11 "Wraith" (reiver), one "FighterBoss" (Zedek), 8 imps, 8 demons, one red skull key, one phoenix rod, and one huge yellow skull key.

Cheat codes involving keys may render the player permanently stuck, given that some "keys" are not vanilla keys but placeholder objects tagged to scripts affecting inventory. The custom death sequence of falling into the sky separates the camera from the player thing until respawn, which means the player dies even in god mode, and ZDoom's resurrection cheat is ineffective.

The section with the shrunken player is implemented by simply duplicating all visible rooms at a larger scale and teleporting the player during each cutscene, hence the enormous yellow key referenced above.

All demons are flagged to run a script when killed which spawns a "demon heart" item. When picked up, the demon heart executes a script that gives the player one phoenix rod ammo unit, so in essence the demon hearts become ammo pickups for the unmaker.

During the final fight against the heresiarch, the game will also spawn a potentially unlimited amount of pairs of reivers, and the heresiarch itself can summon a potentially unlimited amount of dark bishops. Therefore, if smart totals are disabled, the end-of-level kill percentage may become inflated.

The music tracks are compressed, so a utility such as FMOD is required to export them to standalone.

Inspiration and development
Void was largely inspired by ; the ACS source code file was named and is included as the  lump in the wad.

Some dialogue and voice acting is borrowed from, including the introduction scenes.

The sky tile puzzle was adapted from a puzzle in RTC-3057.

Void will not run with versions of ZDoom prior to v2.0.48, because it uses the generalized PNAMES lump allowing any texture resource to apply to walls, floors, or ceilings. In fact, randi sent a copy of v2.0.48 to Cyb a month before its public release, for the purpose of testing this feature.

Trivia

 * The player's TID is set to.
 * The evil player clone has a TID of.
 * The original readme optimistically recommends ZDoom v2.1, which wouldn't be released until 2006.
 * In the 2003 edition, the opening cutscene was not skippable. It may exhibit slight compatibility issues in later ZDoom versions, such as the cyberdemon's following a different route or killing the scientist (but the imprisoned marine in the later cutscene is a different thing, so he appears regardless).
 * The unmaker must be wielded to know how much ammo it contains. The RCKT count in the status bar always refers to the Doom rocket (obtainable via the backpack), even though that rocket can never be fired without cheating, and the unmaker otherwise behaves similarly to the rocket launcher.
 * Void should not be confused with .Void (dotvoid.wad), a Legacy deathmatch map by Exl.