The first one. Without a shadow of a doubt.
1 is actually a survival horror game, whereas two gets so far away from that, it is simply an action game with rawr scary monsters. Plus, the last third of dead space 2 is just running through environments, avoiding monsters, not because of low resources or your inability to kill the enemies, simply because fuck fighting them just get this over with.
3 is not worth mentioning next to the other two, although it is a fine game by itself.
(make me copy paste will you! you butt face!)
When i first played DS1 it was so freaking scary i couldnt play it for more than 20mins at a time, and i loved it.
The atmosphere, music, sound design, graphics, gore...just suberb.
Especially the sound design, holy hell.
And thats why its my favorite, second being the second and third being the third.
And i dont even say im a big horror fan or anything, there was just something in that game that pushed the right buttons inside my brain
Constant disappointment with the series after 1.
The first Dead Space by far. It's a classic as far as I'm concerned, and I much prefer its slower, more plodding pace of the Ishimura to the increase in action the sequels took. Isaac just being some guy is undoubtedly the best iteration of Isaac thus far too. He may have been a silent protagonist, primarily characterised by his screams of terror, but rather that than the utterly generic action-man that he morphed into with DS2. Plus the first has the benefit of being the first, so its innovative HUD elements and different take on the horror genre altogether was naturally at its most impressive the first time around.
Though I should add that the segment where you return to the Ishimura during Dead Space 2 is perhaps my favourite moment across the entire series.
Dead Space 2 is my favorite out of the series so far. I loved DS1 since it was such a massive change to the genre with its atmosphere, UI, and gameplay, but it really felt like it was just a tad too long. I felt that all the minor changes done in Dead Space 2 were for the better except for maybe the change in the zero gee enviroments. DS2 really struck a chord with me that was stronger than DS1.
I haven't finished 3 yet, but 2 for sure. It's one of the best games of this gen.
Oddly enough, I disliked the first game. I didn't find it even remotely scary, so it being more horror-focused wasn't as big a plus as it should have been, and I hated the "hey, go fix ANOTHER thing" mission style. I've warmed up to it a lot since then, but my first impression was largely negative. I still hate the asteroid turret sequences, though. Fuck that part.