Apparently the worlds first combined FPS/Tower Defence game. I know I can't be the only one who bought it during the Summer Sale... While it's not a game you'll play forever and it does have its weaknesses, I was pleasantly surprised to discover that it is a hell of a lot of fun! Once having set your base up, you zone down to help your towers fight off the invaders. The game is played in first person, with a map available by pressing tab (you can also select a teleport point to zone to if you've built them). Sanctum Game Review - PGN I'm keen to try multiplayer; who would be interested in setting something up?
I had a hell of a lot of fun playing this for the first couple of single player levels but I needed to go back an finish some of the other games I have picked up and never played. Definitely looking forward to getting back to it.