First starting life as a iphone/android game, Dungeon Defenders has since graduated to an PC/Xbox Live/PSN best seller. This hybrid of action RPG and tower defense has since become a hit with over 600,000 players worldwide. As one of 4 characters, your mission is to defend your crystals against hordes of oncoming invaders, either by your skills or your selection of defenses. Each character class has their own upgradable skills, and unique defenses. Several other classes have been added via downloadable content. The game is even more fun when you join up with other players via co-op. Weather you’re a casual gamer, a fan of tower defense titles, or a fan or RPGs looking for the next big smash, check this out.

Years before Halo’s Firefight, Gears of War 2’s Horde mode, and Call of Duty’s Zombie mode made this style of play popular, Killing Floor made co-op survival popular ammongst FPS gamers. Originally conceived as a total conversion mod for Unreal Tournament 2004, The Killing Floor spun off into its own retail game. Playing as one of a group of soldiers, you stave off an invasion of mutated people with a variety of weapons. You must survive each round by any means necessary, be it making it to high ground, barracading yourself in, or simply shooting everything that moves. In between rounds you can buy weapons from the merchant, and you simply play to outdo your score. If you enjoy Left 4 Dead’s brand of co-op survival horror, you’ll love Killing Floor. It’s free to play on Steam this weekend, and if you like what you play, you can purchase it for just $5.