Origin8 has announced that their critically-acclaimed strategy game, Sentinel:Mars Defense, will be free for the next two weeks. This promotion is in anticipation of the release of Space Station: Frontier, the next game from the guys responsible for the Sentinel series, which is currently being beta-tested.
Sentinel:Mars Defense was originally released in February 2009, and was very highly recommended by Bonnie, who called it "easily one of the best tower defense games in the App Store." The game has since spawned a sequel, Sentinel 2: Earth Defense, which was equally well received. If you've missed out the original, make sure you grab the game while it is free. Let this whet your appetite:
It's war. Earth's first off-world colony is fighting for survival against a savage alien onslaught. Mars is under siege and thousands of lives are on the line. Humanity's only hope is you, the commander of the dropship Sentinel. Welcome to the future of Tower Defense.
Deploy sophisticated turret technology across the Martian landscape to halt the alien advance. Protect walls and barriers that block the enemy's path to your base. Upgrade your weaponry, or release robotic drones to repair buildings and harvest resources. Watch the battle for the planet unfold in beautifully rendered, atmospheric graphics.