Yes, the final boss is ridiculously extreme. You can't really expect anyone to be able to make it all the way through that. I managed to get to the "real Ganon" but by then all backup items are gone and there is still more than one fight left. Can you actually expect someone to do this without cheating.
I've done it without cheating but it wasn't fun, a method would be to stay in the furthest bottom of the screens, if there's fireballs on the screen, that's a very low chance you'll get hit by them, another method would be to spam the hell out of that sword. But to be honest, yeah that's also pretty extreme too.
Below, do you mean after this screen or on the current screen? If after, you need to use the Hammer on Robotnik to proceed, if you can't seem to continue on through the battle, it is most likely that you need to use the Hammer on Robotnik, there should also be floor tiles with Lens symbols in the later parts.
I'm in the same boat. I made it past the "real" Ganon, and about 4 fights into the Robotnik final boss sequence, but when the screen goes to the one past the mirror robe with spitting darknuts and fireballs, that's the end for me. How many past this screen are there?
Edited by EddyTheOliveira, 08 June 2013 - 04:30 PM.