The retro theme is great, it really does feel like a game straight from a Gameboy, excellent work on the sprites! Unfortunately I played a few times and couldn't get past the glitch to the boss, I think the pace and difficulty of the first level is good though. I do wish that I could keep playing but the bug is preventing me from doing so sadly. Despite this, I still liked the content that I did play through, nice work!
Thanks for the comment, I'll be posting the fixed version after the jam so everyone who was stuck can play the 2nd level and the boss fight. BUT if you don't feel like waiting someone posted this:
"If you die on level one and hold down the X button on the black screen it respawns you in but the screen doesn't scroll. No obstacles spawn in and if you hold X down long enough it moves you to level 2"
I haven't tested it yet but that could get you to the second level and beyond
PS, it is in fact a working Gameboy game