7 maps, mostly small (except for the last one, which is quite large). Author says they've been tested with 1 and 2 people... it's doubtful larger groups would have enough weapons and ammo. (In most of the maps, larger groups would trip over each other.) Comes with a bunch of bonus physics models.
A four level solo scenario. Mostly well-built, with nice architecture, and decent gameplay. Play would be better, I think, if it weren't quite so predictable (it became pretty clear that when you walked into a room, several baddies would teleport in to fight you; not all that much suspense...). Also, it suffered from a few glitches in mapmaking... terminals and pattern buffers would appear and disappear according to the level's areas... but even covered or retracted, they worked, defeating the purpose of covering or retracting them. On the whole, though, an enjoyable play... the final battle is definitely adrenaline-inducing. (Of course, the fact that you can avoid it altogether is another question-mark...)