This is good for your first game! It's really common for jammers to not get around to everything they wanted to add. I'd say it's actually the norm so I wouldn't feel too down about it. Audio is something that is especially commonly neglected. Those additions you wanted do sound like they'd really add to the game if you wanted to add them post-jam.
I'll suggest a few minor things since you want feedback. I'd change the scrolling speed of the ground since it feels out of sync with the enemies and the obstacles. I'd like more options for keys or a way to rebind them. And I also recommend adding more game feel such as particle effects. I think those things could elevate this even more!