The level design is pretty solid and time-tested. It's pretty much identical to the original E1M1. However, where it really lacks is enemy variety. Most if not all the enemies you will encounter are spawn and those are tricky to deal with. The original level was also never meant to accommodate them, so not the best place to fight spawn.
Easy skill is still decent because you still have health pick-ups and guns, but in other skills those are substituted by other spawns. A ranger can't subsist on spawn alone, I should detract some points for that.
