Half-Life: Every Game Ranked Worst To Best

10. Half-Life: Decay

First up at number is Half-Life: Decay, the only title in the series to feature any sort of cooperative multiplayer. As the last of the Half-Life expansion packs developed by Gearbox Software, Decay arrived belatedly in 2001 as part of the PlayStation 2 port of the original game.

Ideally, it aimed to take advantage of split-screen multiplayer on a console, but ended up falling short. You play as the lesser known scientists Colette Green and Gina Cross as they carve their own path through the Black Mesa research facility, having some minor influence on Gordon Freeman's escapades.

Half-Life: Decay isn't all that memorable and certainly pales in comparison to both the 1998 classic and other expansions. The first person action isn't nearly as engaging and the weak story is further diluted with two players messing around in the levels. It's one saving grace is the cooperative play, something that lends the game its own unique moments, even if it doesn't fit the franchise as a whole.

One thing Decay can be credited for however, is providing a base concept for future efforts. Valve would return to cooperative modes with a more puzzle focused formula ten years later with Portal 2