9 maps. There are some really, really good ones here... the last three are a lot of fun. Emphasis is on vertical movement via silent, fast elevators. Lots of sniping positions-you'll need to experiment with teleporters to figure out what goes where. You're rarely safe, even on the larger levels...
10 more levels, in the same vein as Demolition 1... Get these and maximize your carnage!
If these maps remind you of the Suicide series, it's because the creator of that series got the three Demolition collections started. All three of these collections have 10 maps in them. Most in this set are modified M1 Bungie maps (very much in the spirit of the first few Suicide maps, only with better texture alignment. Great flow, more weapons and ammo than you can ever use, no aliens. Very nice.
The third of 3 nepacks (10 levels each). This one's mostly original. Inspired by the Suicide series, these maps have the same play feeling, but more attention has been paid to details. Very nice maps.