This game had quality written all over it, from start to finish. the gameplay is awesome, the storyline, again brilliant. Follows up dead space 1 beautifully. the graphics are also of high quality, as are the controls.
A wide variety of challenge, easy is as it says easy, but good for new comers. and then you've got zealot for a proper challenge which is very hard, but more satisfying.
Best part though would be when you've completed it on the hardest level (unlocked after completing on any level) and play through again to get the 'hand cannon'. This is basically a big foam finger that has unlimited ammo and Issac makes an awesome 'peew' shoot noise when firing, like i said pure genius and worth the fustration of all challenges before.
I got this for 43quid and thought it was worth every penny, so at 25, it's an absolute bargain. It would be hard to find a game that compares at the moment!