Nice to see more people attempt C64 stuff
Fist off I marked some char errors where you have more than 3 colours.
I would suggest less style more structure.
Also some of the detail texture is just there for the hell of it but does not really add anything (esp the bit on the cheek on the left).
The chin / lowerjaw / neck area looks very ambivalent. It looks like we should either see a bit of the bottom of his jaw. Either that or you made his chin too small.
If I was you I would try to map out the main volumes at first before adding stuff purely for style, and even when you do that you should try to make it look more coherant. The outline of the hair and body does not really go with the face imo.
Don't give up tho, this is not easy, and what you have here is a good start. Keep on pushing!