Definitely nailed the retro feel. Found it cool that you managed to implement two seperate palettes and all the optional Wildcards. Impressive amount of enemy variety too, both in type and how they behave.
For improvements, I did find Jumping a bit janky (I am Gen Z, so maybe thats a retro thing). I would prefer if you could hold a directional key, and then jump to jump left/right.
Very polished submission. Nice one!