some confusing stuff here. the terminals always tell you if you need to return back to them, there is not a single instance where you are required to grenade jump (besides a secret in the third level) and there's music throughout the game (2 and infinity don't have music though)

i found the map design pretty intuitive - much more so than most doom levels - but to each their own there

For final boss, did you whip his orbs to make drumsticks appear? It's kind of a funny thing they put in, since I think they meant for the fight to come off more cinematic than difficult after the boss rush beforehand.

@Memoats yeah, the stage 8 difficulty spike is pretty much the only blemish I really have against this even after tons of playthroughs. The hitboxes on the spike platform thingies are insanely big.