In a word, brilliant. Sewage is an incredibly well designed, lengthy, and more importantly fun map created over seven years ago but still holding its own. There's no real story to it, you start out in a sewer system and your goal is to find your way out and blow up as much as you can along the way - not the most original of stories but it'll do. Puzzles are terrific. Instead of just collecting cards and hitting switches, you'll have to make use of the environment to progress through the level. Jumping through the middle of interlocking gears, finding alternate routes, it's all there and there's 200 sectors to spare. Great fun, check it out right now!