I beat the game yesterday. Very good game overall. I wish there'd been a melee weapon like some kind of cool engineering chainsaw but I understand having a weapon where you don't have to worry about ammo would take away a lot of the game's tension. There were several times, especially toward the end of the game where I had less than a clip of ammo in my guns. That would make it very exciting going into new areas with so few resources. But still, having you temporarily pick up some kind of cool melee weapon for half a chapter or something just to deal with a massive wave of guys might have been a really cool, gory sequence.
I'm not sure if I will play through it again right away, maybe tear through it with my fully upgraded Rig, Plasma Cutter, Kinesis and Stasis for the One Gun achievment.
I have a love/hate relationship with games that use the "protagonist doesn't speak" conceit like Half-Life's hero Gordon Freeman. On the one hand it really draws you into the game but on the other there are times when your characters lack of dialogue just makes them come across as... well, peculiar. Like with the girlfriend Nicole, you'd think he'd be a little more verbal whenever she contacts him throughout the game.
Overall though Dead Space is one of the absolute best single player games I have ever played. Bring on Dead Space 2!