timeshift

because i want to try it 

No!
Looks good but even that gets worse as you play further. Computer AI is crap, collision detection sucks, the time rewind mechanism is neat in theory but not necessary for gameplay and I never used it.

You could do 10 times better if you have a 360 and maybe 5 times better if you have a ps3 and looking for FPS

Some better games you may wanna consider that are not bioshock or halo...FEAR, Unreal 3, front lines fuel of war...

front lines fuel of war...

is that a good game 

^Yep.

One can brag that it looks good and that you control cool vehicles and that it has 50 player online blah blah...

Its just fun to play...while Timeshift is not.

 If you have a 360, go to marketplace and download the demo's

I actually downlaoded Front lines, I enjoyed it. Timeshift was cool, but then again it was just the demo I played. 

its okay. it's a cool idea, but was done poorly.