Seems like nobody is able to figure it out, unless they knew right away..perhaps someone who knew it right away can pretend he had to guess, and post the answer + new pics.
Would do it myself (the pics, that is) but no time to look for some now.

Okay, I'll try and get it going. This one is fairly easy.

Looks like Silent Hill, but I can't quite place it.

It's getting very hot, but you'll have to give me the exact game ;)

The fact that I can't place it, usually means that it's "The Room", but I could be wrong.

And it is! Silent Hill 4: The Room is the correct answer :)

Worst part of the series by far. This is Silent Hill! I play it for the atmosphere, not for the battles, so why would they include immortal enemies?
This is one of my favourite PS2 shooters, but it was originally a PC game, so you should know it. The technology was amazing, but as usual it was followed by a sequel which simply ripped out everything that made #1 so wonderful.

looks like Red Faction

Correct. Loved the way you could transform the environment and dig ways where no developer had meant you to.
Anyway, your turn.

To be honest SH 1 was the only game I had tried prior to SH 4. They both suffer from mediocre graphics and tank controls, but otherwise the atmosphere is great!
I can agree that the overly aggressive AI and tight corridors forcing you to fight is a bad idea though.

That clue was too much really, I only saw the demo, and got the nagging feeling that the much hyped destroyable terrain would be nerfed in some way.
Anyways, here's a little something that I never got around to completing, for one reason or another.

#2 is usually agreed to be the best part. There are no serious battles (heck, the final boss takes 5 shotgun shots on easy), you can chose difficulty individually for fights and puzzles, some very, very, very different endings, a great story and the overall most frightening atmosphere I have found on any game so far (Siren: Blood Curse comes close though). Eventhough there are virtually no battles. You'll find yourself sneaking around, looking behind you whenever you hear a noise.
#3 is not quite as disturbing, but still pretty good.
If I had to put the games I played into any sort of order it would be
Silent Hill 2 > Silent Hill 3 > Silent Hill 1 > Silent Hill Origins > Silent Hill 4

X3: The Reunion?
Or maybe Freespace, but it looks too pretty to be that.
Edit: Well, Andy sure got me there :'(

I'd say Quake 4... haven't really played it, but that's pretty much the first thing you see after launching the game (I think).

You're.... RIGHT!!!
Thought I'd fox you all with an intro shot. Guess you ain't fooled that easy!