Release date: 2010
There are plenty of first-person shooters out there, and not all of them are worth playing. That's not Singularity, though. The campy sci-fi shooter involves a secret communist research island with plenty of time travel to send you back and forth between the past and the present as you unravel its numerous mysteries.
But best of all are the guns and powers, like a sniper rifle that lets you guide individual bullets and a massive stasis bubble that freezes whole groups of enemies in their tracks. You can fill them up with bullets to watch them all slump over in unison when the bubble pops; it's even more amusing than it sounds.
Singularity's campaign is a quick ride, but at the budget price that you can definitely find it at these days it's totally worth it.