Coffee Stain Studios says its PC FPS/tower-defense game, Sanctum, is now available on the Mac. Mac gamers can download the hybrid shooter exclusively through Valve’s Steam Store currently for US$8.99 (http://store.steampowered.com/app/91600/), 10% off the regular price.

Here's how the game is described: "Sanctum is a fresh take on the tower defense genre and places the player right into the frenetic fray with tight first-person shooter gameplay mechanics. Gamers take the role as Skye, an elite soldier sent out to protect her home town, Elysion One, from hordes of mysterious alien creatures.

"To successfully defend land, players must construct and upgrade a labyrinth of defensive structures and towers. When the havoc starts and the wave of baddies is unleashed, gamers jump right into the action with fully-upgradeable weapons to play a key role in the defense. Sanctum has taken the best features from FPSs and tower defense games to create something totally unique."