Couple months late (delayed by the pre-order goodies), but it seems scenic; I toured E5M1 and E5M2 on easy mode for babies, but now I need to restart at a real difficulty.
Like Romero's E1M4, it's way too dark. Just groping thru black spaces. It wouldn't make the levels worse to have a little better visibility.
I love the shoot-the-eyeball mechanic for switches. The standard Doom switches where you shove your face in a wall and then a bunch of walls open up is still kind of annoying.
I play Doom maybe once a year, and even after 26 years it takes me only a couple seconds to get my groove back, start weaving and shooting like a pro again. Gonna make a few runs at it this weekend, see if I can get thru.