Four levels, although two are transition/informational. Some really cool tricks, and very high-quality map construction... but I had trouble getting into a level that's 50% underwater. Other than that one gripe, though... there is some really cool stuff here. Definitely worth the download. Great map, good construction and nice lighting tricks, can be played co-op, we are testing it and it will also be posted as network level later. When you play this one sit down and take some time....Some of the doors aren't just doors-I got smashed and was caught off guard a couple of times..The rest you will have to figure out yourself.