The stolen sound effect from Commander Keen is funny at first. Until you hear it 50 times that is. And then it is followed up with all those stolen sound effects from Doom on top of it, the teleport sound, the flip switching, the door opening, the rocket launcher in the last level, and it kind of pisses me off. The only thing that WASN'T a sound effect stolen from ID software is that godawful beeping at the beginning and the godawful music that played all through it. A pity you didn't rip off any of their video game music while you were at it. You could credit it and it would mostly be forgivable too.
And then comes that awkward moment after you've run into 50 walls when you realize that you could go BACKWARDS the whole time, moving forward while turning to the left, and moving forward while turning to the left weren't your only options, you could also go straight and backward. Boy did the game suddenly get a whole lot easier when I discovered that. Virtually every level is easy peasy if you just do it slowly. Well once you get chompers and the bugzapper circles that turn white then you can be in a hurry but it's still about going slowly because there will be safe spots where you can camp until it is safe, and you can meticulously turn around by going back a little bit and forward/turning a little bit repeatedly.
By the way, it's REALLY easy to win the last level (level 19) with the rockets. All you have to do is hold down the "shoot button and hold down the left button so you go in a small circle and never stop shooting. Or the right button. I don't know if you intentionally realized you had such a gaping weakness in the final boss level there.
It's a functional game with no actual bugs per se but it's disappointing. I think it crosses the line from homage to ID software games to just flat out stealing their sound effects since the game itself wasn't an homage to anything of theirs but rather something original (which on its own is good), and it was a tedious game to go through but not very hard. Tedious but not very hard is not a good combination.