Too complex by half!
MAINTENANCE COMPLEX (2complex.wad) is big. Really big. You wouldn't believe how impossibly big this... yeah all right, but let's put this into context. It's about the same monster density as Doom 2, but there are 1000 monsters. I've done this map twice now, once with savegames to get to know it, and then today without using them I finished the map with 100% of everything after an hour and fifty five minutes. That's how big it is.
What's more amazing is that the entire map is also filled with roughly the same level of close detailing that must have taken ages to make. Nowhere looks empty. Having said that it is rather messy. Not much is parallel to the axes, which is all very well but leads to texture alignment weirdness as you can never get the lines quite the right length for the textures to fit them properly. It's thousands and thousands of packed linedefs and sectors, and it goes on forever.
Although it's nowhere near randomly textured or STARTAN everywhere or anything like that, there's no particular overall theme either. Some of it is factory, some of it is city, but I'm pretty sure if I looked I'd find every single Doom 2 texture in there somewhere. There's machinery and computers and brick and stone and slime and blood. It's crowded but it works for me. However some people might call this map ugly, especially with one section of factory full of Wolfenstein guards.
Gameplay: As I said it's pretty easy, especially when you know where the secrets - all twenty three of them - are. It's typically top-heavy and the start can be tricky, your health might get dangerously low and your shotgun might be nearly empty, but after the first fifty or hundred monsters you might well have a megasphere, backpack, chaingun and two shotguns and be off on your way. There's always plenty of resources around, indeed only once after that did I think "oh well I'm going to die now" (this was after about 280 monsters, not the bit with the cyberdemon in the library or the two teleporting archviles that manage to resurrect an awful lot) but I didn't and then soon found a soulsphere and some armour and I was off again.
In fact the worst thing that's going to happen to you is that you're going to get completely lost. If you miss a switch or something there is miles and miles of map to search. It took three hours of game time spread over three days, with much searching in the map editor, to finish it the first time. Then as I said above, two hours to play even when I did know it. The map is so densely packed that it's hard to trace out a route on the automap. There is a computer map at the end but you have to get there first, that's helpful for secrets though of course. Amazingly though I don't think I found anywhere in which I could get completely stuck.
Also, here's a tip: when you get to the aforementioned library, up on the shelves, and the roof raises up and the cyberdemon appears, don't fall off the shelves; try to get the invulnerability so you can charge the thing down. You can't get back up there unless you go the long way round, because the way past the key closes off when you pick it up.
So in summary, if you have infinite reserves of patience, this is probably the easiest thousand-monster map I've done. I don't know how long it took the guy to make but with the amount of messy, haphazard detailing on display, well put it like this it'd take me years. Sometimes I wish I could be that enthusiastically slapdash about texturing instead of an obsessive perfectionist, but there you go. It's old school Doom 2 texturing on an epic scale. Not for everyone, not the kind of wad I'd play every day maybe, but still very enjoyable.