It's very similiar to the style of play that the Royal Marines Commando had, if you haven't played that game basically you are in a 3 man squad. You have 2 AI characters following you around. They open doors and save your arse (on more than one occasion). This game has awesome weapons, they are fun to use and get the job done - shooting enemies results in painting the walls red with blood. It is rather brutal actually
but of course fun 
The level design is rather simple corridor stuff but it does change mid way through the game to be a bit more open then goes back to the corridor fighting. I actually prefered the corridor levels myself. The battles with the AI were just more fun up close. The AI are pretty smart, they will do the usual retreat, duck for cover, fire from cover and even smack you in the face when you get up close.
The storyline is alright, but the game is definitely a bit on the short side. It's a simple run & gun deal, nothing much fancy. The game also has a multiplayer and there are actually people playing it online still. I had a few games and it was pretty fun.
It's worth the cheap price on Green Man Gaming if you have the spare cash.
Checkout some gameplay footage here:
Glad you got a winner. 