Get Dead Space for free via Origin. The PC version actually isn't very demanding so even if you have a somewhat crummy computer it might be worth your time to download it.
Dead Space came out back in 2008 and it's currently holding down a score of 86 over at Metacritic. I played it a while ago and found it to be pretty enjoyable. I'd compare it to Resident Evil as far as game play goes, although you're allowed to move while shooting. The story is pretty interesting and the creatures are terrifying. The core mechanic of having to completely immobilize your foe by shooting off their limbs is pretty satisfying, especially when a slow motion mechanic is introduced later in the game to help deal with large hordes. I'd recommend people who enjoy 3rd person shooters and horror games to give it a try. If you aren't a fan of 3rd person shooters or horror games you should still give it a shot because you just might like it. I'd never played a horror game or 3rd person shooter until I got Resident Evil 4 on a whim and now it's one of my favorite genres.
One of my favorite games ever. The sequel was great, can't say that about DS3, since I never played it; but let's just say I think it looks bad.
People are complaining that it's on Origin, but a free game is a free game and that game happens to be Dead Space.
Other than a couple years ago when a coupon glitch made a lot of their games free, I don't think so. This is the first I've seen them offer a game for free. They do have decent Steam level sales from time to time.