A lot of people complained about the audio being too loud. That is true but I have a different opinion about it. I wouldn't use 8 bit sounds for this game, I would use something more realistic. I just think it would work better for it. Go Owlboy, if you know what I mean.
I do have ONE problem with the visuals however. The clouds make it too difficult to see anything. You don't have to change them, I would just give the bullets a higher contrast just so they are easier to see.
One more thing, I could forgive all that if the game just had more content. I would give more weapons.