The Suffering, and it's sequel The Suffering: Ties that Bind, are being removed from GOG (I don't know if they are being removed from other online storefronts), so if you want them, then get them now.

They are first person shooters that can also be played in third person, and are most notable for having very imaginatively designed enemies. The first game is set on a remote prison island, where the dead are coming back to life, in a form reminiscent of how they were executed, and it is really creepy, and you play a man on Deathrow (because he murdered his wife and children, though perhaps he is innocent of those crimes...) who has to fight to get off the island.

The second game takes place after the first, in mainline Baltimore, and isn't as good if you ask me (the 'hostile spirits coming back to life" thing doesn't feel as convincing when it's set in a mainland city, the sequel has a two weapon carrying limit, the sequel isn't as long, etc), but it's still enjoyable and well worth playing.

GOG have put the games on special offer (£1.69), so if you want two really good and atmospheric first/third person shooters then pick them up for next to nothing before it's too late.