Hey Major, I played through Drowning, gonna add my two cents.
The start is great as it causes the player to initially panic, and then try their best to play it safe. Nothing wrong with the next few areas, but the room with the PE needs a bit more ammo in it. I was running around with 14 bullets after that when I had that room full of imps to fight, which is never fun. Also in that room, you don't provide a teleporter out if they fall which can confuse the player. It wouldn't be so bad to leave the teleporter out, but you also force the player to wait on a raising platform near the dark at the end, which can cause them to initially run off the first time into their death.
In the next room with the razor thin platforms, it might be nice to have a couple imps about to provide projectile fire, as it's not really that threatening until you run into the specters. And then the next room... you need to give some more ammo here too. I had to skip an HK since I didn't want to chainsaw him. The walkway with health on it is fine, as the imps provide some nice fire, but maybe you could throw a caco or two in to provide some mobile fire. Also, the RL platform is switch-activated but uses the same texture as the pedestals in the previous area (which are not switch-activated), which is a big no-no to me. I say just put it on the ground and let the player chance getting damaged to pick it up, or at least change the texture. And the door to the teleporter secret needs the walls unpegged since the texture slides down when it reveals.
In the next room, the mancs provide no challenge as you can zip past them, and the one AV is easily subdued. Add in one or two AVs in with him and you could provide enough pressure on the player that the mancs could easily come from behind and provide some hell. Through the tele, I don't think the arrow on the ground is needed as long as you put some more blue torches surrounding the "wrong" side of the wall. Past that, the cacos take too long to get to you and the cybie can be easily skipped. Requiring the player to take a lift to the tele would be better, along with bringing the cacos closer so there's an infight possibility with the cybie. Also, the side walls for the tele are untextured.
Past that tele, you warp in a baron which is cool, but in that size of a room, he can be disposed of. Making the room smaller, or replacing him with 2 revs will push the player out. The walkway ahead is good, but mancs would provide better pressure than cacos, especially since the walkways are linear. Then you have a teleporter on the following island that takes you back a few rooms. TAKE THAT OUT. Replace it with the teleporter in the water directly ahead of the player. No one wants to forcibly go backwards in the map, unless that's the theme (like Fear of the Past).
Past that, more untextured walls are revealed when the floor crumbles. After that, the player has no incentive to go backwards and fight the demons since they can just go through the tele and run into the exit. At least provide obstructions so they can't just zip to the end.
Unlike fiend though, I love the expansive feeling of the map. Seeing the vast ocean in front of you, all of which is lethal is pretty frightening. The only problem is that the gameplay is made haphazardly, rewarding the player more for running than sticking a battle out. It's fine if that was your intention, but it just makes UV maxing the map a chore.
Also fiend, I was thinking about map order, and now that major's map is going to be split into two, maybe we could reorganize it a bit. This is what I was thinking.
We could start the level set off by putting the player onto the coast location at the bottom left part of Spider Island, introducing them thematically to the island of terror. I would save Whispers in the Dark for much later though, since it is more of a chaotic and dark map. And I would move Meat Train forward since all weapons are given in that slaughtery map. Also I was thinking what we could do to link Vertigo Limit and The Sigil together is make the exit of VL the bedroom of The Sigil, having the player warp there, or go through the front door to reach it. That's just my idea though, since I like continuity.
01 - Spider Island part 1 (Outskirts)
02 - The House that Fear Built (according to Major's theme)
03 - Pain Consumes
04 - Spellbound
05 - Blood Urge
06 - ????
07 - Spider Island part 2
08 - Drowning
09 - Ruin Me
10 - The Meat Train
11 - Whispers in the Dark
12 - Vertigo Limit
13 - The Sigil
31 or whatever - Cacophobia
I have slot 6 empty since the EP2 sky only works at level 12 and beyond, meaning that we need to put another map in if Cacophobia is to be our secret level. What we could do is take split Spider Island up one more time and put another level there, or we could take a crack at making a short and simple level that would fit in at like MAP03 and move the rest forward. I could probably make up the bare bones of a simple fear map if you wanted to fill it with enemies.