First two levels are Wolfenstein 3D - tier corridor fests (albeit quirky), not very engaging, but after that the maps become much better. Huge vistas in an underground cavern, silent teleport fu***ry and heaps of small neat details. Very oppresive atmosphere at times.
DooM maps have a langauge of their own. You know what you expect from a DooM map. Monsters, keys triggering traps, there is an assumed flow. I love it when maps subvert these expectations, and while these maps do not go full chaotic (and there is a balance, it cannot be too random, there does need to be a theme), I love how the world seems to be tearing at the seams, and about the only thing you can cling to as familiar to a DooM map is killing Demons.
So yeah, I guess you could say I liked it. Too bad it's so short. Hopefully Shrooms 2 exit the Mordeth hell.