Wanted to add, the game looked great in fullscreen, and at that point I started to realise why it's such a large filesize 
I'm testing and playing it in fullscreen, so yeah, I hope it looks good

Are you making the sprites yourself? They are also first class!
Sprites have been found and adapted. I guess my original post wasn't accurate. I'm developing this game as art director, programmer, and game designer.
New screenshot added to OP.
Added 2nd boss fight, levels 7 and 8. New enemies. Buffed the Speed stat upgrade.
Please let me know any feedback you have!