Refreshing change from traditional tower defense games. It's tough to pull myself away from this game.
Sanctum takes some of the best elements from traditional tower defense games and adds the unique twist of allowing you to get in there and fight the enemies from a first person shooter (FPS) perspective. It works incredibly well and I've gotta say it really adds to the fun when you're down there in the trenches fighting it out against the enemy. I look forward to more games combining the tower defense/FPS genres.
For me this game is a real gem. I'd rank it among the very best tower defense games I've played, second only to Defense Grid. Also, if you enjoy this type of game I'd recommend checking out Orcs Must Die which is scheduled to come out in October 2011.
In summation, it's well worth the measly $10 purchase price and it's an absolute must buy if you enjoy tower defense games.