Half-Life: Decay
Half-Life: Decay is a multiplayer-only expansion pack for Valve's first-person shooter Half-Life. Developed by Gearbox Software and published by Sierra On-Line, Decay was released as part of the PlayStation 2 version of Half-Life in 2001. It is the third expansion pack for Half-Life, and like its predecessors, Decay returns to the setting and timeline of the original story, albeit portraying the story from the viewpoint of a different set of protagonists: two scientists working in the Black Mesa Research Facility. Decay is a cooperative multiplayer game, designed to be played by two people working together to pass through the game's levels.
Summary from Wikipedia, available under CC BY-SA, read 5 September 2026.
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- Released
- 2001
- Developer
- Gearbox Software
- Platforms
- 1 systems
- Critics
- Not scored
- Steam Deck
- Unknown
- Download
- Not stated
The record
| First released | 14 November 2001 |
|---|---|
| Developer | Gearbox Software |
| Publisher | Not recorded |
| Platforms | PlayStation 2 |
| Genres | First-Person Shooter |
Source. Catalogue facts from Wikidata Q796776, seeded 30 August 2026.
How long is Half-Life: Decay? How long to beat it
Total play time for Half-Life: Decay is about 5.1 hours to do everything, and around 3.5 hours to reach the end of the main story. These are player-submitted times from HowLongToBeat, not our own, shown with the number of players behind each.
| How you play | Hours | Players logged |
|---|---|---|
| Just the main story: straight through the critical path | 3.5h | 28 |
| Main + the extras: story plus the side content most people do | 4.5h | 7 |
| Completionist: everything: 100% the game | 5.1h | 5 |
Source: HowLongToBeat community submissions, read 2026-10-19.
Where Half-Life: Decay sits on the grid
The grid places every game in the catalogue on measured axes rather than on an opinion. This is where Half-Life: Decay lands on each map it has the data for, with the share of the catalogue it beats on each axis.
- Year
- 61ahead of 15% of the catalogue
- Reach
- 43ahead of 83% of the catalogue
Percentiles are against the games that carry a reading on that axis, not the whole catalogue: counting a game with no figure as a zero would flatter everything that has one. How the grid works.
What readers say about Half-Life: Decay
Reviews written by people who have played it. These are separate from the GamingPickz Score and are never averaged into it: that score comes from thousands of Steam reviews with a sample-size correction, and a handful of unverified ratings would distort it rather than improve it.
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Where Half-Life: Decay appears
The ranked lists and finder pages Half-Life: Decay qualifies for, from its own genre and platform to what it takes to run.
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Part of the Half-Life series
Half-Life: Decay is one of 12 Half-Life games we track. See the whole series ranked by the GamingPickz Score, plotted on the grid, and listed in release order:
Common questions about Half-Life: Decay
What platforms is Half-Life: Decay on?
Half-Life: Decay is available on PlayStation 2. It first released in 2001.
Who made Half-Life: Decay?
Half-Life: Decay was developed by Gearbox Software.
How long does it take to beat Half-Life: Decay?
about 3.5 hours for the main story, 4.5 hours with the main extras, 5.1 hours to complete everything, from HowLongToBeat's player-submitted times. These are community medians, so your own run may be shorter or longer.