List of maps to improve certain Doom skills

In terms of monster centric maps, there isn't a lot to learn that you can't already learn from Doom 2. As obvious as it is, monsters are the same in every wad. Fight em a couple times and thats all you need to learn what they do. You just need to spend some time examining what they do instead of killing them all the time.

IMO, the primary challenge of Doom is just avoiding damage as much as possible. Everything else is secondary. Always assume there are no health items ahead and treat every situation like youve got 1% health. A good practice warm-up that works for me is to play a very projectile-heavy map such as MAP13 Downtown or MAP16 Suburbs, and dance around monsters as long as you can without killing them. Just try to stay alive as they hunt you down. Aside from the obvious parts like aiming competently and managing your ammo, all monster encounters boil down to being an enforced time trial for dodging projectiles. So practicing surviving forever versus killing is great practice for making yourself very resilient in harder maps.

For dealing with hitscanners, playing the first episode of Doom in nightmare or with fast monsters on is good practice. Theres a lot of health and ammo to hold you over, and you'll get a lot of practice intuiting when monsters start to shoot. If you treat all hitscanners like theyre on fast monsters mode all the time, you can keep yourself from taking a lot of unnexpected damage.

For slaughtermaps, managing crowds is a pretty unique skill that isn't very common in Doom. The toughest part is not getting boxed in and clawed to death, so sometimes it helps to go pacifist again and dodge crowds of pinky demons without hurting them like in MAP08 Tricks n Traps, MAP18 Courtyard, or the spectres outside area of MAP19 The Citadel. Since these are pretty big areas, you might want to try some bullfighting with them and let them get close to closing you in to see what quick getaways you can make. All monsters generally move with the same sort of pathing. Pinkys are among the fastest and most focused so theyre probably best to practice that with.

Theres other important skills like being able to straferun for quick escapes or across difficult gaps, conserving ammunition, and causing infighting but those are mostly skills acquired through practice in any map I think.

Unfortunately I feel there is a pretty big problem in the Doom community in that most maps don't really hold your hand with giving you the skills to survive the really hard stuff. The best looking wads often have an agreed understanding that you've already played all the known hard wads before it. This puts a pretty big barrier of entry for new doomers that I'm trying my best to address with my own mapping and the Doomer Board Projects I lead.

I've personally played several thousands of doom maps over the last 15 years, which has given me the confidence to say you really can't be ready for everything. Even when the rules are fair -- as in you get the right weapons and sufficient ammo to kill everything with, there's quite a few maps that simply have bullshit encounters in them or require you to be on high alert the entire time. I'm talking about "hot starts," traps in which you can't possibly know what's going to happen without dying to them first, or lousy thing placement where new monsters are alerted for every step you take. It's unfortunately, a very common side effect to "overtesting" your maps, especially if you're doing all the playtesting on your own.

Another tacky thing you can do to save yourself some trouble with bullshit hard maps is to just do a kamikaze run by rushing through the map and pressing all the switches as fast as you can. You'll likely die of course but at least you can get a quick glance at everything that will happen to you so you'll have an idea of where the trouble spots are when you start playing the map seriously.

The only maps I can think of off-hand for monster-specific stuff are Scythe 2 MAP14 (a very revenant-focused map) and New Gothic Movement 1 MAP03 (a cyberdemon massacre with a BFG and millions of cells.) but I'm not sure these maps really do enough to prep you for harder maps.