Endless Loop Studios has released a new version 1.06 patch for Survivor Squad adding Mac OS X support to the action/strategy game as well as a one-on-one multiplayer mode where one player controls the squad of would-be survivors and the other spawns infected to thwart them. A free demo is available to sample the game, and it is on sale this week for 50% off. Here's a trailer showing off the game's new multiplayer support.