Maybe a bit on the easy side on skill 3, most of the areas could have used more enemies as they felt kinda empty, particularly the large outdoor area with the pipes. Only part that sort of got me was the end with the shamblers, although I kinda cheesed it.
And there's certainly an abundance of secrets, I looked quite carefully and still only managed to find about half. The positioning of the quads could have been better as the first ten-fifteen seconds of most of my runs were spent searching for the nearest enemies, and then I only encountered a few at a time.
Aesthetically it reminded me of the classic late 90's era of maps, in a good way - made me feel slightly nostalgic. The pipe constructions in the outdoor area were neat, if perhaps a bit jarring juxtaposed to the otherwise low-def architecture. The layout and flow of the map was logical, and I always appreciate slopes and ramps used for progression as it makes for some fun jumping maneuvers. Goes to show that maps don't necessarily need to be massively detailed behemoths to be entertaining.
Overall a pretty decent map, and certainly good for a first release, but it would have been even better if it wasn't so sparsely populated.
Link to playthrough
Spent some time at the end unsuccessfully searching for the hidden rune buttons.