I've slowly been working my way through the Half-Life series over the course of about six months and so far they've all been consistently strong.

Decay seems to be a bit of a runt of the litter, as it struggles with repetition, a lack of variety, and little to no interesting dialogue and character interactions; all shortcomings that were not in any way a concern in Half-Life, Opposing Force, and Blue Shift. That being said, I still had an incredibly enjoyable experience with the game, mostly due to it indeed being: a Co-op game.

Even the most flawed cooperative games can still be hilariously fun if you find yourself playing alongside a pleasant player 2. Thankfully I had my best friend to accompany me through this game and we plowed through in probably two hours, despite a bit of game crashing bugs and soft locking that I'm unsure was a cause of the game itself or a result of our chosen method of emulation. I've chosen to give the game the benefit of the doubt in this case and decided that these bugs could've very well been our own fault.

What Decay really excels in is it's fun co-op puzzles that must be solved to complete most every mission. The formula behind these puzzles are for the most part always the same:
1. Encounter obstacle that impedes progress for both players
2. One player has to stay behind to solve the issue while the other proceeds ahead.
3. The separated player now has to find a way to allow the other to rejoin them.
It's a pretty cut and dry formula that I would have believed myself to grow quickly tired of, but the variety of ways Decay implements these puzzles, helps them not overstay their welcome. There is an especially neat laser puzzle on the second to last mission that both me and my mate had difficulty wrapping our heads around, at first blush. But upon understanding, was undoubtedly one of the neatest in the game

My biggest gripe with Half-Life: Decay is the bland and anticlimactic final mission and ending. While each Half-Life entry up to this point has had epic final battles, in Decay, players operate a piece of machinery while battling hordes of Vortigons and Grunts, much like in Blue Shift, only this confrontation is far longer, takes place in a far less interesting landscape and mostly consists of waiting. Even opening the portal to Xen in the original Half-Life would’ve made for a more engaging final confrontation than the one in Decay, because at least the player would be receiving some visual stimuli, rather than just: “This is a desert. Hope you like waiting for audio cues from uncharismatic NPCs.” Truly a let down of a finale.

Despite the hangups here and there, this game was still truly one of the most fun Half-Life experiences I’ve had, because as previously mentioned, I got to play alongside someone who made it a good time. If you have a friend who would be willing to enjoy the co-op of Half-Life: Decay with you, do give the game a shot. Otherwise, I doubt you’ll be able to redeem all too much if on your lonesome.