This is interestingKurt_Woloch wrote:As for the sprites, there are different size balls in the arcade version... the purple ball where the snake hatches from is the biggest one, the red balls are medium, and the green ball is the smallest one.

By the way, in my opinion you should decide by now if you want a full Q*Bert graphics, or a "rip off" with changed graphics in the CreatiVision style.
In case two, I think I could design a spaceman as main character (I would use 2 colours for the suit), and several monochrome "aliens" as enemies. No need to use "balls" or "snake eggs", I think I would simply add alien faces, coils, small cubes or pyramids, etc.
Carlsson: do you want animated sprites (2-3 frames), or do you want 1-frame enemies?