I need some feedback for my spritesheet

[AkumaTh]

Pretty much what Hiynastrike said. If you want an example of how to convert a sprite from one style to the SMB1 style, simply look at Super Mario Maker and their Chain Chomps.



The SMB3 has more details than in SMB1, but at the same time they did more than remove colors. Since the SMB1 style is more flat (everyone is either straight toward the player or the screen), they made the Chain Chomp look like he would fit in the original game. They still have less colors and no outlines, but you can still see the details. 

Your Shyguys don't show off that detail level. In fact, the way you recolored them made them lose detail. You removed their arms. You should instead try to edit the Super Mario Maker Bob-ombs and use them to make the Shyguys. Or do what I did and base them off Goombas.