Summary: Lot's of fun, but I suggest using a game controller if you have one. My X-box 360 USB controller worked perfectly. I'm an older gamer (>50), and this game was very challenging for me even on the easy setting. So I ended resorting to a trainer (I use a pay service). Even so, the game was a lot of fun, nicely staged and again "challenging".
Summary: I feel just like a space marine. I hope there is a sequel, there is room for improvement with less linear maps and variable leveling up, but I enjoyed the game the entire time. Maybe a bit graphic for kids, there is some blood.
Summary: I player single player on PC with keyboard and mouse. I didn't have any problems with the Steam system on my Vista system. Though the game seems a bit cartoonish while you are going through the training scenes it gets much more serious later on. The artwork is very detailed and the acting is good. Very British. You will slug it out from beginning to end and enjoy perfecting your combo moves.
Summary: Pretty much the first thing you do is jump out of a dropship and punch an alien warship as you land. Then, you do things that are more awesome. Repeat for four or six hours, and you've got one hell of a game.