The gun glitch in level 1 is the same as original version. If you shoot the powerup above that stilt house, it lands up there. So, not really the hack: P
Gun glitch in level 2 is actually intentional. Shoot the powerup before it goes over the null ground: D
The boss defeat glitch (in pit) is really just the how the game functions for this given scenario. With the limited programs we used to hack, there was not much we could do to this. The game still progresses, so it's not too big deal.
We could not modify the demo's after the title screen either. But Super C's data is not well documented and there isn't too much we could work with.
IMPORTANT NOTE:
Again, the final level has 2 paths to take near the beginning. You should easily come across it. If it matters that much, I recommend only a save-state there (or maybe not
) and find out which path does not glitch the final boss XD