Mike Tyson's Lunch Out Constipation! in da Club Residence Malevolence In Space... Kim Jong Unpossible: A POE Heist Starring Tom Cruise Toilet of Yo Momma
A Big Mess: Pretty much all of my ideas kinda fit within this theme. The title was just a throwaway idea, but the more I thought about it the better it fit.
Chaos: Give the player lots to deal with, not in a way that's unreasonably difficult, but just enough so that it's impossible to avoid all damage and there's a need to seek out resources.
Use all the features: Doom, its derivatives, and eternity have a lot of gameplay features---for example, slopes, portals, friction, and many more---that go underused. I will use all of them, hopefully more than once. This gives maps a unique flair and hopefully exposes more people to what's possible in the game.
You can run past stuff, but it'll make your life harder: I find big hp walls very obnoxious especially for when I know what I'm doing. So, traps are designed to make gameplay more interesting whether you're skipping something or not. Hp walls punish players for playing "as intended" (if you believe in such a thing) with boring combat and players trying to move fast by uhhh, not letting them do that.
Doors and walls are stinky: They're not always bad, but consider the alternative. Levels built around high ground divisions allow for different parts of a map to interact with one another, adding to the chaos. If a level doesn't let you see other areas relative to where you are, navigation is a lot harder. If a level is just a sequence of unrelated combat scenarios (a symptom of walls and doors), its not that interesting. Doom levels should be taken as a whole. Sunlust Map 20 is my favorite map and its a prime of example of this.
Toilets: I think Cyriak infected me with this idea that more toilets = better Doom level.