It's a puzzle solving fight. I didn't make it, it's from the official release, I just needed to adjust the coding to work for the mod. There are actually 2 boss fights from the official release, I'll test out the final boss later. At the moment I really need to make parallaxes for the new Otherworld areas related to this boss fight, cause the slowdown under normal gameplay will be a huge hassle (game doesn't have slowdown if you play without replacing the system file after editing but that doesn't give the player the full screen needed for the boss fight).