Gunstar Super Heroes (U) sprite priority issues

[fleroviux]

this game is notorious for rendering incorrectly in many emulators.
the solution is simple: account for the per-scanline maximum cycle count for OBJs (as mentioned in GBATEK) and skip remaining OBJs / pixels if the limit is hit.

EDIT: if you don't do that yet, you also need to render OBJs in forward order.