I'm sure many of you are familiar with the old Lemmings games. For those who aren't: It's a puzzle-platformer where you have to guide a herd of little rodents to a designated exit by assigning a limited number of different skills (e.g. climbing, parachuting, digging, building a bridge) and in each level there's a set amount of lemmings that has to survive. Lix is an open-source Lemmings clone (for Windows/Linux/OSX) with added multiplayer, automatic replays, highly configurable hotkeys, savestates and many other cool features. Here's a cool video that showcases it excellently and even features some advanced strategies like the Distance Leap or the Rebound. You can find the game here. Overall it's a great game and I'd be happy to play some multiplayer with you guys