"In the first level, which is primarily indoors, the game plays somewhat like Doom 3; that is, you walk through tight corridors and rooms punctuated by Strogg leaping out from behind corners. It's made a bit more interesting, however, by the presence of your colleagues, who reinforce you both with words and bullets. That rather obvious conceit actually made a considerable difference to my enjoyment of the game. I've always enjoyed cooperative modes in games, and even if they're just computers I'd rather have some buddies by my side. It also keeps the game moving at a brisk pace since you're always aware of what you're doing and why. Most action games that are this scripted just aren't going to be particularly non-linear, so everything may as well be spelled out for you while you focus on the shooting and the not dying."