So many inconsistencies....

Not to flog a dead horse, but you can tell the bosses were programmed by different people just by looking at the $00BF to $00CA range of bytes. 

You see $00BF used for bosses with more than one stage to the battle, such as Death. The problem is, only Death uses it. The Bone Dragon sets it before fleeing, but then clears it immediately - it wasn't even being read, from what I could tell. Dracula doesn't use the variable, nor does the wisp. 

Bytes $00C9 and $00CA are bitmasks for the bosses with multiple parts getting hit and then momentarily stunned. You see it used in the Mummy boss. Oddly, the bitmask is 16 bits deep, but the Mummy boss only uses two bits, and both the Skull Knight and Baphomet use just one bit. The Bone Dragon doesn't even use the bitmask, nor do any of Dracula's forms; we could probably chalk this up to both being impossible to stun. To confuse matters, only Death's second form uses the bitmask, and I don't recall that being stunned. Then again, it could be like Baphomet where the stun duration is only 4 frames. The Bat boss is the one boss that you would be forgiven for assuming it used this feature....

I still haven't figured out what $00C1 and $00C2 do, although I am guessing they are another 16-bit variable pertaining to one of the bosses. I don't know which. Two unknown variables possibly pertaining to a boss? Pazuzu's platforms? Nope. Moat Dragons? Nope. I still have yet to check The Creature, Doppelganger, Grant. What's so important about $00C1 and $00C2, you ask? Namely, you cannot swap characters when either byte is set. Medusa's petrify? Nope. I'm stumped.