90% of the maps are crap free and very good to excellent. Only a couple pissed me off, mostly because of excessive and confusing teleports. And if you're just after a basic Doom blast, it's probably best to avoid the secret levels. You can always warp to them later. All they really have is retro novelty value and that wears thin in about 3 minutes. Not much good for actual play. Other than that, highly recommended AND it's vanilla friendly.
Lovely puzzle-centric map that was a little more action-packed than I remember. Progression made sense and I didn't find myself wandering for too long without finding some way through the level. If you get lost in this level the automap helps a lot and gives some hints as to where the next area to explore might be hidden.