Xbox Live Arcade this week. The first way -- and definitely the most fun way -- is by a process of elimination. You see, of the seven titles announced for the Days of Arcade event, Lode Runner is the only one that hasn't been released yet. See, logic is fun!
If you'd rather be boring and have someone just tell you, the game was also confirmed on the latest Major Nelson podcast during an interview with the game's producer and designer, Brett Ballow. The game will include online and offline multiplayer and also a level editor(!). Now that we've gotten everyone nice and excited, the price: 1200 ($15).