Defenders of Ardania is a new tower defense game from Paradox. As well as organising and upgrading a series of keeps to make a mazy city of death, you'll be training and controlling troops to try and push back the enemy hordes. It's not all about defending, mind. Multiplayer modes will let you attack your friend's fortresses, or you can gang up to take on AI opponents.
With three different races and a brace of elf-squashing spells to hand, it looks as though Defenders of Arcania could bring a bit of extra depth to the oh-so-addictive tower defense formula. Check out the Defenders of Ardania Facebook page for more.