Thank you for the feedback! Looking back, I do wish I had a tooltip show up explaining how to progress through bosses (something like the text that appears before you start a level telling you to hit all sides). And for the second and third levels, I do agree that some of the yellow phase walls move too fast, which just happens because I wanted to keep every wave a similar length while also keeping the difficulty. Just some waves ended up being dumb diff spikes and just insta-killing the player without prior knowledge.
And about the music, I just messed up a setting at the very end and I had three seconds left, game jam + college crunch time goes crazy!
But I appreciate the comments and always appreciate ways to make my projects better. Thank you for making my day!