I'm working on a cpz edit

I'm guessing your level art has a lot of extra blank 8x8 tiles at the end, try deleting those and it should fix the art issues.

 

Or is attempting to load 0 bytes, which actually makes the VDP to DMA 65,536 words (yes, double the size of VRAM, wraparound FTW). I don't remember the exact details but if the art is either 0 bytes or a multiple of 4KB (in uncompressed form), this can happen in the way it's implemented in the game.

Somebody else probably can come up with the details about how to fix it.

 

This is really cool. I love the second act. After the first REALLY big loop, you can't go back through it. I don't know if you ment to do that. If you are in a ball through the really big loop and go out of screen, you get stuck in the wall.

I love this level! I had to put the debug code in to get to Robotnik though because the level is not finished to that point.

 

The Hud and rings come back if you go into the special stage. Im not sure if that helps, but atleast you have another Clue. Also, this is a very nice level design! I like the use of death egg tiles.