Final Zone Eggman Laughing Fix - RetroKoH/S1Fixed GitHub Wiki

(Original guide by Joer489)
Source: SSRG thread
Commit: 000f33b

There is a minor bug with the Final Zone boss, in which Eggman laughs at you after being hit for the final time. Due to the flickering caused by sprite limitations, it's nigh unnoticeable unless you are actively looking for it, but even then, it can be hard to see without using Frame Advance in an emulator. It looks something like this:

Fixing this is quite simple. Open _incObj/85 Boss - Final.asm and look for loc_19F96 All we need to do is add a simple check, and branch past the instruction that triggers Eggman's laughing animation. We can actually branch past setting the animation, along with the AnimateSprite instruction below, like so:

loc_19F96:
+	; If Eggman is defeated, don't display the "laughing" animation and branch
+	tst.b	obColProp(a0)
+	beq.w	locret_1A01E

	move.b	#1,obAnim(a0)

Now, Eggman will no longer laugh as he retreats in defeat.