Some feedback.
Pros:
. Game/mod is definitely very unique. The cartoony feeling its trying to capture is done very nicely.
. Really liked the exploding enemies. Smooth animations and feels good to just blow those enemy shapes to pieces.
. Sound effects complement the game very well.
. Graphics are done very well.
. Music score fits perfectly with the theme. Kudos to the composers.
. "This is my boomstick" cartoon variant.

Some suggestions that you might like to consider:
. I plan to play this proper but just out of curiosity, I tried to see the full weapon set. The selection is nice but feels a bit inconsistent. Some weapons slots have two weapons (which is good) while some have only one. Also, weapon slot 6 is missing I believe but weapon slot 7 is there. I'd suggest filling up the empty slots as this will make weapon selection feel a bit smoother.
. A bit more enemy variety would be nice. I noticed the maps are a bit huge-ish so it might be beneficial to have a slight bit more variation in enemy types early on. Nothing drastic of course.
Overall, great job Jimmy

. Keep up the good work.
Also, do you really plan on releasing this as a stand-alone game? I definitely think it has the potential to do nicely without having to rely on Doom.