Great game, very fun. Would love to see more levels and perhaps for future editions a difficulty setting of some sort. Went through it a little too easily and it left me wanting more, which I guess isn't a terrible thing :).
Shandos, just so you know, you do use the mouse in this game. Like in many popular fps games, wasd is used so you can have one hand on the keys and one hand on the mouse easier. I'm heavily right handed, but find the wasd setup very easy to use.