I got up to level two before running out of ammo and dying. I feel like I missed a weapon, I only got pistols, shotgun and rocket launcher. Machinegun would be really nice to have even since the very start because the enemy composition calls for it.
Levels feel quite long because of how stressful dealing with enemies is. Second level has some amazing stuff in it even if it's unfinished. The ambushes could be toned down - Doom can get away with it because projectiles and enemies are slower.
I like it, but I would prefer to play it in a bit shorter segments due to the level of attention needed around enemies.
Enemies are really disturbing for some reason.
Restarting a level resets brightness setting.