Nothing too exciting... But also not too bad
Well when I read the title I thought that it would be a flash about the Book "Knee-deep in the dead" but its just a simple Doom movie.
The sprites you used weren´t bad at all. I liked the idea that the Imp is riding a pinky demon. But the backgrounds looked bad. If you can´t draw the backgrounds so good you should better use a sprite background.
The sound was okay - only the speaker was a bit hard to understand sometimes. All in all it isnt that bad but also nothing I would watch twice.