Thanks! Glad to hear that it works on A4000 now. That's a neat suggestion about 2nd button, I did this quick version for testing. If you enable up for jump on the menu, the second button automatically defaults to special weapons:
https://www.mediafire.com/file/e22e9k7zq0eraw7/CastlevaniaAGA_WHDLoad.lha/file
About speed, for the stock CD32 at ~14MHz it's using a method that adds performance/extra bandwidth but in exchange you get the screen off center.
You may see many Amiga games from back then (Fire & Ice AGA) or recent (BD vs Dragon Ninja AGA) with off center picture. I personally prefer some slowdown here and there - even NEO GEO games have, it's part of the experience - than oddly off center screen. :) But here goes another version for such testing w/ the method enabled:https://www.mediafire.com/file/qgwd1v0w2mnsm9x/CastlevaniaAGA_WHDLoad_offcent/fi...