Ah, Dead Space. A few flaws aside, Visceral's grand tribute to sci-fi horror tropes was a rock solid little game that, nearly a decade later still holds up very well, especially in terms of visuals. Two parts Resident Evil 4, one part System Shock and with a twist of Event Horizon to taste, it's a stern blend that still has what it takes to mix it up and leave players feeling a little shaken.
As part of their continuing On The House range, EA are giving away the first in the series completely free, so long as you buy it via their own storefront, Origin. Once you've tagged the game, it's yours to keep forever, and it should be available for the next month or so if you're not feeling too quick on the draw. Still, best to click that button sooner rather than later.
As a general gameplay tip, I highly recommend varying your weapon usage. This will make the game harder , but a lot more interesting. Due to its shameless imitation of Resident Evil 4 in so many aspects, Dead Space doles out ammo drops based on your current equipment loadout, meaning that if you strip yourself down to just the starting plasma-cutter pistol, you'll end up with more charges for it than you'll know what to do with, and all your upgrades will go into it exclusively.
The end result is that if you try to be smart and min-max the system, you'll have an easier time for sure, but the result for you as a player is a vastly more monotone and less enjoyable game. It's a bit like the folk who played through the entirety of Bioshock using just the lightning power and the wrench, only to complain that the combat wasn't varied enough at the end. Don't be that person. Please.
Oh, and a minor technical warning - the PC version launched with some irritating issues that were never patched, including broken V-Sync support that caps the game to 30fps, and mouse controls that get bizarrely squirelly when V-Sync is disabled. Thankfully these can be worked around, and you can find the solutions to both of these at the PC Gaming Wiki. I highly recommend you heed their advice. Dead Space's many strobe effects really require V-Sync to work right, and 30fps looks wrong in general.
Dead Space is completely free via Origin. Grab it here.