Speaking of Map 07, i definitely gonna use it for some inspiration if I ever use OTEX in the future. I also loved how you need to calculate all your steps if you don't want to waste ammo.
BUT for the love of god, thin elevators and and monster ambush (the arena on the screenshot above) is something like toothpaste and orange juice together especially if you have to reach all the goodies with an elevator, I would give the player some more rocket/plasma earlier to deal with the revenants at least.