The theme was simply "metal", which gives a lot of leeway. It was followed to varying extents, from maps entirely made of the stuff, through others that were half metal half brick, to the last one which was just kind of random.
Difficulty: almost all the maps are difficult. Most are small, not greatly populated but with a very high monster density, map06 probably being the most obvious example. There were a couple of larger slaughters, e.g. map12.
Wish it had more weapons. Got bored of using the pistol so much. The first archvile was too much for where it was placed.
Not bad. Quite messy but I liked that. Too many crushing ceilings, though. Impossible to avoid.
A large map; a sequence of disjoint confrontations; a bunch of monster teleporters that go off far too slowly; and an interesting bug whereby somehow monsters can walk out of their holding areas into void space. I think it's due to silent line teleporters, another Boom feature that breaks far too easily.
Quite a nice inclusive layout but it was too tough. Need more and bigger weapons earlier to deal with the monsters it throws at you. I could have probably dealt with the archviles or the revenants but both at once was too much.
This one was really nice, a simple layout that crosses over itself and back to the start, wide corridors and high ceilings and enough resistance to be fun but not overwhelming.
Ouch, monsters everywhere, can't move for them, no ammo...
Lots of brick, and more high ceilings. I like maps with a feeling of space to them. Was a bit strung out, somehow. You run around the whole map twice and it's kind of empty. But it wasn't too difficult. I could have done without those pain elementals at the start, though.
This map is more or less one corridor stuffed with monsters and weapons. I managed about half of it before the four archviles teleported in, and there were two cyberdemons in the exit room. It was a bit much for me.
Two rooms, vaguely similar in that they both want you to go up a big wide staircase. Lots of traps and ambushes. Shame about what was behind the red door, it seemed like maybe the author ran out of time there. Or maybe it was to lull you into a false sense of security for the next trap. Also this is a good example of a map where a forced weapon change can be annoying (I won't spoil it, you'll know when it happens)
Three rooms plus the start area. Each one is not bad but they're completely disjoint. Monster resistance is quite strong in several places.
This is one of those maps where you start in a cage and have to shoot a button to get out, which wakes up a horde which starts teleporting in. Two problems. Firstly, some of the teleporters don't work. Second, I had no idea how to open the exit. It's not obvious at all that you're meant to push on one of the three demon-face boxes.
A slaughter map. You basically fight a bunch of monsters and press a button that opens up a new area. Repeat several times. It plays quite well, especially once you've opened up more of the map and have enough room to start playing tactically. I really liked this one but that might just be because I fluked a 100% run of it.
This one is spacious and has a really nice inclusive layout that manages to avoid disjointness almost entirely, so in that sense I really liked it, but the gameplay was too tight and I kept dying stupidly. I guess I could have done with more ammo or something. Note, the BFG does not need a archvile jump to reach it. I thought it did and wasted a lot of time trying. (You would get it a lot earlier though.)
The final map is somewhat off-theme and very retro - it even has a thin ledge-walk to a super shotgun, it's that oldschool. It's not without its charms, being very open and high-ceilinged, and has some good battles. Unfortunate that the lift behind the red door only works once, though. Can easily render the level unbeatable, especially since the first time you call the lift it'll almost certainly have a bunch of revenants on it.
In summary, I guess you can't expect too much from speedmaps but many of these were good.
(Of course since the thing was made over 5 days in a dwforums thread instead of strictly over a couple of hours in some irc channel you can't know how many of the maps are actually proper speedmaps, but having said that I didn't bother to read the thread and find out the minutiae of how the project was made)