A very large, and I mean LARGE, net map. This thing will take a bunch of marines to keep it interesting. A bunch of large rooms that are connected by some very large open corridors. The corridors lead to other large rooms or upper tiers for sniper posts. Enough ammo for a very big group, guns were hard to find at first, but they are there, keep looking. I found this to be a very good, very large net map. The problem with the water pools is that I only found one way out, gernade hopping, up and out. (which really takes a beating on your shields) There might be teleporters, but be prepared. Supports Koth, EMfH, KtMwTB and team play.
A solo level with no save term. You'll find yourself doing it several times, as you run into each new trap... and parts can be pretty repetitive, but it's a fun half-hour or so. Fun terms.
A large level with a few open areas, a suicide room, and lots of passageways that look the same. The room with the fluctuating pool has some neat features, though...
A pretty cool small level designed for two players. You face each other across a lava moat. Both have a large wall to hide behind, but your opponent can raise yours with a well-placed projectile, leaving you defenseless... and for those who believe the best defense is a good offense, you can build a bridge across the moat (although it's not necessary-you can simply run across, using the alcoves on the side).
An arena level with a large pool in the center. Half of the bottom rises and falls slowly, making a good high spot (or missile block). Teleporters speed up end-to-end travel, and light switches control who's visible and who isn't...
A KOH map with the hill surrounded by movable platforms, sitting in lava... relies very heavily on fake walls (walls that aren't really there, but that look fine until you run through them). Several secrets, and lots of switches, the use for some of which only becoming apparent when you hear the screams...