Hello! I'm currently working on a sheet for Sonic Jam 6, stuff like the title screen, continue screen, etc. and I wanted to see some feedback on it so far.
If anything you should tidy it up and remove all the useless empty space.
Just throwing my two cents in here- empty space was pretty big back in the day but now with more complex image editors it’s easier to re-arrange sprites to reduce the clutter.
Also, try to avoid using bright magenta as a background color, a more dull color that contrasts well with the sprites themselves would be a better fit IMO. Otherwise, not bad for a first rip.