Played the demo round 3 am this morning and could't beleive how awesome it was! The single player mode has a great story, some nice horror elements and the Atmosphere is amazing! I noticed a lack of music, but I rather liked it alot. There are so many sounds and effects in the game if there had been any game music it would have sounded out of place.

Portholes, boxes and wall walking.

Imagine walking up to a box laying sideways on the floor in the middle of a room. You look into the box, but instead of seeing the inside wall, you see a whole other room!! You look up and down seeing a vast room that you can walk into, the sense of disorientation is great. These boxes somehow lead to other parts of the ship that contain even more strange objects. For instance, one of these boxes early on leads onto the surface of a miniture planetoid suspended in the middle of a huge room, with it's own gravity and you can walk all the way around the surface of the planet.

Portholes are basicaly holes in time and space the Aliens use to pop out of nowhere and start shooting you. While it doesn't sound impressive, these things really are. Combined with the wall walking(imagine the tracks that Samus uses on Metroid Prime to climb walls and the ceiling in Morph ball mode) a situation may and does occur where on the ceiling above you, where you just walked down from, a porthole opens and several enemies jump through and start shooting you. At first you can't figure out where you are getting shot from. "WTF?!?!" you may ask as you look back and forth trying to spot them, only to realize it's coming from the ceiling. This... is fun.

The wall walking is a great part of this game and the game in general is alot more appealing to me than most recent FPSs. This one ended and I was so mad, I wanted more!!!

It's so much fun all the elements of the game seem fresh and new, the weapons are well designed as are the levels and puzzles, not to mention it has great action and some stuff that really makes you jump back from the screen a bit as you try and fend of some weird mutated Humans.
Not to mention the graphics are truly next gen, with great lighting effect and it has a very immersive atmosphere. I loved the fact there were no actual cutscenes, you are part of them and you can control what you look at and all that, makes it seem much more real.

Can't wait to get the full game. This demo gets a 9.9 outa 10.