Half-Life: Decay

Half-Life: Decay is an add-on included in the PlayStation 2 port of the first-person shooter game Half-Life, developed by Gearbox Software and published in 2001. A PC version of this game was released September 23rd, 2008, developed and released by independent Ukrainian developers with the help of other European developers/fans.

Like Gearbox's other expansion packs Opposing Force and Blue Shift, Decay returns to the setting and timeline of the original story, but with different player characters: two female colleagues of Gordon Freeman, Dr. Gina Cross and Dr. Colette Green. Dr. Cross is the model for the Hazard Course hologram, and can be seen at a point in Blue Shift. Dr. Green is a new character invented for Decay.

Although Gearbox completed a PC port of the game, Decay was never released "due to powers beyond Gearbox's control". As such most Half-Life players never got a chance to play through it. Decay is also not available through Valve's Steam service. As of September 23, 2008, Decay has been successfully ported by the fan-based team at for the Half-Life engine. Download it on this page.

Weapons
The player is able to obtain most of the weaponry found in Half-Life excluding the Gauss gun, the Gluon Gun, and the Tranquilizer Crossbow. Also, in "Xen Attacks" the player gets the opportunity to play as a couple of Vortigaunt Slaves, thereby giving them the power of firing energy bolts and hit other NPCs with their claws.

Gameplay


Unlike the other narrative-based Half-Life games, which are single player only, Decay is designed for co-operative play. While it can be played by one person, swapping between the roles of Dr. Cross and Dr. Green, the game is intended to be played by two players in split-screen. Various puzzles and combat situations throughout the game require the co-operation of the two characters.

The game is also unique in the context of the Half-Life series by being the only game divided into separate missions, instead of a single unbroken narrative.

Decay has a ranking system for all of its nine missions, ranging from F (worst) to A (best), based on accuracy, number of enemies killed, and damage taken. If all nine missions are achieved with an A level, a bonus mission, Xen Attacks, can be played as a pair of Vortigaunts, R-4913 and X-8973.

Decay is also the only game of the series where it is possible to fight and defeat a Xen Manta ship, which serves as the final boss.

Trivia

 * Decay was originally called "Hazard Team", but this title was changed so as to fit with rest of the names in the series. The map file names still bear the "ht" prefix.


 * In the original Half-Life, Gordon Freeman sees two other empty HEV suit containers when he puts on his hazard suit. These containers are intended to belong to Gina and Colette's HEV suits, who have already taken them by the time Gordon arrives.


 * Half-Life for PS2 includes a code screen in the option menu where cheats can be activated. Two undocumented cheats were discovered by the project leader of Decay's PC port. One of these cheats allows the player to unlock all ten Decay missions, including the bonus mission "Xen Attacks". The second cheat causes the game to prompt for an expansion CD. This expansion, consisting of an extra set of bonus levels, was only released on the Sony Underground demo disc of the June 2002 issue of PlayStation Magazine, and was never officially announced. The bonus levels are actually a port of Half-Life: Uplink.


 * A glitch in the PS2 port allows the game to play as Gordon Freeman. Simply save a game in the main game and load it at the start of Decay.