Corridor 7: Alien Invasion

Overview

Corridor 7: Alien Invasion is a first-person shooter developed and published by Capstone Software using the Wolfenstein 3D game engine. The game takes place in 2012, where a team of scientists bring an alien artifact from Mars to a top secret underground facility in the United States known as Corridor 7. When a vortex is opened from the artifact, leaving the military base overwhelmed with aliens, a lone Special Forces agent (you) must stop the invasion.
 
The game was originally released in floppy disk format in March of 1994. An enhanced CD version was released on May 6th, 1995, containing more weapons, enemies, levels, as well as multiplayer and CD audio. A sequel to this game, called Corridor 8: Galactic Wars, was under development using the Build engine. It was canceled after Capstone went bankrupt. One of the programmers recently released the prototype to a Corridor 7 fansite, which can be found here.
 

Gameplay

Corridor 7 plays like traditional first-person shooters of the time. One key difference is that the player must kill a certain number of aliens per level in addition to finding the exit for each level. The difficulty choice not only determines the number of aliens spawned, but the number of aliens required to finish each level. 

• Corporal - Few aliens. Only 10% of aliens must be eliminated to finish the level.
• Lieutenant - More aliens. 75% of aliens must be eliminated to finish the level.
• Captain - More aliens. All aliens must be eliminated to finish the level.
• Major - Even more aliens. All aliens must be eliminated to finish the level.
• President - CD version only. Major difficulty. Features a customizable randomization factor that scatters all the items in the level.
  

 
The floppy disk version contains 36 levels (6 of them being secret levels). As the player makes his way through the levels, the architecture becomes more alien-like. The CD version contains 10 more levels that take place in the alien homeworld after the player enters the vortex. (Which have teleporters instead of elevators and no kill requirements) The CD version also contains 8 deathmatch levels for use in multiplayer games. (The first of those having a striking resemblance to the first level in DOOM)
 

There's an assortment of items to aid the player in his quest. For example, the player has a visor that is capable of infrared (to detect hidden enemies and traps) and night vision (for dark areas). The player's visor is also capable of showing an automap (known as proximity map) that shows a limited amount of the level. (Which can be expanded by collecting a Floor Plan item). The player can also collect and use proximity mines.
 
Other items that are scattered around to pick up are charge packs (which recharge alien weapons only), ammo packs (which increases your max ammo count), body armor (which gives you 200% armor), adrenaline bursts (which temporarily increases your health by 300%), and invulnerability spheres. Health can be replenished by both medic pack dispenser walls and special "health chamber" rooms. There are also dispenser walls for grabbing regular ammo and recharging your visor battery. Instead of keycards, the player activates a working computer which unlocks all the doors of that color (red or blue). But beware, some computers instead trigger the alarm (which angers the aliens).
 
Multiplayer in the CD version can be played in both regular deathmatch and team deathmatch. Because of the limitations of the Wolfenstein 3D engine, the firing animations always face forward. Players can choose between the standard marine or one of the aliens, which have unique speed and health.
 

Weapons

There are five weapons in the floppy disk version of the game. They use one of two types of ammo: regular, human-made ammo, and alien ammo.

• Taser - The fallback weapon that requires no ammo. Short-ranged and weak with a slow firing rate.
  
• M-24 Close Assault Weapon - Starting weapon (along with the Taser). Faster firing rate that is good against weaker enemies. Uses regular ammo.
  
• M-343 Tribarrel Power Blaster - Despite acting like an automatic shotgun, it can take out aliens at long range while not sacrificing power. Uses regular ammo.
  
• Alien Dual Blaster - Main weapon for the alien military (and thus uses alien ammo). An alien machine gun that does not use much ammo.
  
• Alien Plasma Rifle - Alien rocket launcher (using alien ammo) that fires a large plasma ball that explodes upon impact, damaging anything within its blast radius.

The CD version added three new weapons:

• Assault Shotgun - Deadly in close range, weak in long range, and a very slow firing rate. Typical shotgun that uses regular ammo.
• Alien Assault Cannon - Faster-firing version of the Alien Dual Blaster.
• Alien Disintegrator - Similar to the after-effects of DOOM's BFG-9000 blast. Very powerful with a high alien ammo consumption.