I enjoyed the map! It looks awesome for only 4 hours. I did, however, find a couple bugs. There's an imp stuck behind a wall in the room with the blue door. There is also two deaf imps in the monster room with the vent. So it is impossible to get 100% kills without noclip.
Also, The secret was pretty interesting. I would have never known to how to get in without looking at the map with Doom Builder.
EDIT: I noticed the file you linked to here was different than the one you uploaded to /idgames. Looks like you just forgot to delete the stuck imp.