|1994 - 1995 - 1996 - 1997 - 1998|
1999 - 2000 - 2001 - 2002 - 2003
STRAIN (STRAIN.WAD and STRAIN.DEH) is a 32-level partial conversion for Doom II released in 1997 by the Alpha Dog Alliance. It features nine new or modified monsters through the use of DeHackEd, modified weapons, and a soundtrack written by David "Tolwyn" Shaw, Mark Klem, and Jon Landis. The project had a sporadic development history, exceeding a year due to cyclical interest and disinterest .
The WAD was originally released as a self-extracting LHA file split into four segments, each meant to fit in the 1.44 megabyte storage of a 3½-inch floppy disk, alongside a batch file named unpack.bat. This can only be run in DOS or Windows. Using it creates a DOS program named strain.exe which must be run to unpack the WAD. Because it requires DOS, strain.exe cannot be run in 64-bit versions of Windows, requiring the use of DOSBox. However, the batch file must not be run in DOSBox, as the emulator does not interpret the file-combining feature of the DOS and Windows "copy /b" command correctly. This package is available on the idgames archive in strain10.zip.
On June 24, 2015, Eric Baker created and uploaded a separate "repackaged edition" of STRAIN to the idgames archive that consists simply of the contents of the LHA, including the required WAD file and DeHackEd patch, with the original strain10.zip bundled with it for copyright reasons. This package was made due to the difficulty of unpacking the original release for users without either DOS, Windows, or the knowledge of DOS and Windows necessary to do so. When the files are extracted from this version, the WAD and DeHackEd patch can be loaded directly into a source port without any further user interaction. It is available on the archive as strain.zip. A similar repackaging was also created by Andy Olivera for the Doomed Speed Demos Archive in 2008, but without the original release bundled with it, and is the version provided for download on its demo page.
STRAIN occurs after the events of Doom II. A military officer in a secret base on the Earth's moon has been engineering demons, creating a new breed of Hellspawn which breaks free of its confines, making an initial landing on Earth. The Doom marine undergoes an experimental treatment to increase his combat potential. Its side effect is that it leaves virtually all of its subjects in a state of perpetual, murderous aggression. The in-game story follows four episodes as the marine fights to an infested spaceship that has landed on Earth, afterward battling his way deep into the heart of the secret installation where the demons originated from.
2. ^ Arranged by Jon Landis.
STRAIN modifies the original Doom weapons as follows.
- The marine punches quickly with both fists in succession. Both swings are boosted by the berserk powerup.
- Pistol fires faster.
- Shotgun has new graphics and fires faster.
- NFG replaces the plasma rifle. Its base damage is seven points higher.
- Psychic Blaster replaces the BFG9000. It consumes three rockets per shot, launching partially invisible projectiles at a faster rate that only cause blast damage.
STRAIN makes several other core gameplay changes.
- Players begin with no ammo at pistol start.
- Cells are capped at 50 (100 with the backpack).
- Megaarmor sprite is replaced and increases armor to 300 percent.
STRAIN features a number of new monsters. The most basic monsters (zombieman, shotgun guy and imp) are unchanged, as does the arch-vile. Cacodemons, hell knights and barons of hell fire faster projectiles. The heavy weapon dudes have new sprites but are otherwise unchanged.
- Strain Imps replace arachnotrons. They appear identical to an imp with a higher-pitched alert noise. They move incredibly fast and have slightly more hit points. Attacks begin with a brief pause, after which they stand still and throw fireballs at a steady pace. They're able to infight with regular imps.
- Strain Demons replace demons and are recolored to bright red. They are significantly more durable than regular ones.
- Holo-bots, replacing revenants, are wheel-shaped, flying one-eyed robots. They fly very slowly and fire both types of revenant missiles, which travel at a much slower pace. Holo-bots also appear in a partially invisible variety.
- Dopplegangers replace lost souls. They're similar to lost souls in appearance, but their eyes and the top part of their flame is blue. They attack with an imp fireball before charging, and are also able to use the imp melee attack.
- Ministers of Pain are miniature cyberdemons, with much less health. They fire normal rockets (only one at a time, as opposed to a regular cyberdemon's three-rocket salvo) but are vulnerable to blast damage.
- Polydrones are flying cubes that resemble spawn cubes. They attack with the spiderdemon's chain shotgun. Their corpses are fiery wrecks that damage the player at close proximity.
- Demon Lords replace mancubi. They are similar to barons and hell knights, but colored white; they are much tougher, being the most durable monsters in STRAIN. They attack in several barrages of five green plasma attacks spread in a wide arc.
- BFG Troopers look identical to zombiemen. They attack with BFG blasts.
- "Vacuum Demon" is an unused monster that replaces the SS Trooper. It is invisible, incredibly small and fast, and can kill the player in god mode. The STRAIN team made it to simulate death due to exposure to the vacuum of space in certain sections of the story's moonbase but did not implement it in the final product.
- MAP07: En Route is impossible to complete in ports based on old versions (prior to 2.3.0) of ZDoom, as the level relies on the occurrence of a spechits overflow in order for the exit to work. Recent versions of ZDoom identify the map and automatically apply the required compatibility flag. There are also problems with the DeHackEd patch when it is used with Doom Legacy. Doom Wad Station provides a fixed version at their STRAIN Page.
- MAP09 originally appeared as MAP04 of Dystopia 3.
- MAP23 originally appeared as MAP10 of Dystopia 3.
- Holger Nathrath's levels were likely donated outtakes from the cancelled Serenity IV project, according to Sam Woodman's notes in . Nathrath attempted to donate such maps to the Eternity TC and Sam Woodman's megawad, Testament of Judgement.
- There are a few examples of continuity. MAP18 begins in the same hall as MAP17 did. The door that was locked in the previous map can now be entered, and the opposite door that was entered previously is now locked. In MAP22, the player visits the corridor that overlooks the hall. Finally, in MAP24, there is an accessible teleporter in the center of the hall, and the player needs to use it in order to progress.