Pretty cool!
-Love the aesthetic. Grew up with the commodore64
-I immediately wished the Player character had the same art as the rest of the game. Perhaps a white outline box OR the character could be a sprite from that font. like a "0"
-I didn't expect the movement to be so smooth. felt a little out of place. Seems like the default settings. I was kinda wanting to get at least a hint of the stiff C64 platforming controls. I think i'd prefer a little bit of that to be added.
-Awesome death flashing animation
-I'd suggest disable jumping on landing for 0.05 second after (tweak the exact number) - Because I had problems holding W and autojumping after landing. This is per the default C2 platformer controls but you can fix it
-Enjoyed the level design!