An addon map pack for single and multi player games.

Gives you a nice new setting with new geographic challenges, all in all its a nice addon that will keep you enterained for several hours.

Sanctum: Cavern is a DLC maps whose gimmick is teleporters, wait, didn't I say that before? Yes, it's another teleporter map but it has jump pads, yay! But seriously, land is at a premium in this map, you can either make a long row of die for the creeps or make them zig-zag, however, my fav tower/trap makes this map awesome, the killing floor, just spam it with a few towers and you win. Very nice. All and all, a nice little map with some focus on gimmicks. Note: if you are wondering you just get a key to enter into your steam client to unlock the DLC.

An interesting addition to the game. You can single player this map, or you can host games on it. Some were pissed that you had to pay for the map, but the price was decent. Love the strategy.

Overall, Cavern is a nice-looking map. The seting is quite atmospheric, and the difficulty reasonable.

It plays a bit differently than the maps supplied with the base game, which makes it worth trying. It features some nice sniping spots, but you can also get directly into the fray, if that's how you prefer to play.