@chipsnblip Sorry, I posted all the information that I was thought was relevant/actually knew how to provide.

@megafacehead said in Castlevanie SOTN corruption/shaking candles:

Make sure enhanced resolution is disabled.

launch game-open retroarch-quickmenu-options-set enhanced resolution to disbaled.

Exit, relaunch.

Thanks Megafacehead! That worked. It was definitely the enhanced resolution setting. Hopefully this will help someone in the future!

Ok - I've got SOTN basically playable.

Using the retroarch overlay config GUI (select+X in game) I set:
frameskip to 1
custom viewport width 1440 (x3)
custom viewport height 816 (x3)
integer scale on

other settings:
hw biliner filtering - turning this to off makes the game look significantly better on my big flatscreen from apx 3 meters away, but doesn't seem to impact performance (disclaimer that I prefer a pixelated look to a blurred look for my scalers)

other observations:
loading savestates seems unstable until loading a regular game save. not sure if its related to my settings changes or not.