Super Mario Bros custom tileset

[Gors]

More important than quantity, is the quality of the sheets. If your enemy sheets' quality is akin to those of your tileset or Mario sprites, then I'm afraid to tell you your enemies will suck balls.

You have little knowledge in shading, your hues are very saturated and low contrast, wonky anatomy etc.

For character sprites as small as Mario and enemies, avoid using outside antialiasing and black outlines as they make readability difficult. even cartoony characters like Mario and co. have anatomy principles (such as having a column and hip bones, limbs having joints and legs being longer than the torso) so it's good to study it. It'll help you make more realistic characters too so it's a win/win condition if you take some time on it.