Castlevania always had a lot of secrets going on, break wall to get turkey leg has been a standard since the beginning and they spun out from there. The later Sharp Computer version even had some system clock stuff going on.
Ain't got nothing to do with Mario 3.
Castlevania 4 is alright, but there's a lot of janky nonsense going on and I'm not quite sure why the Flop Whip exists. It's an okay game because it's a Castlevania, but it's almost the worst 16-bit Castlevania.
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