SOTN has literally one difficult part -- Galamoth.
And the witches that put up shields are annoying, but you only deal with them once, on the way to galamoth, who you kill, then get the fart cloud that owns everything in the game. but it's still one of those games you have to play all the way through when you pick it up!
oh, but I guess Richter mode is like playing SOTN as a regular castlevania. Pretty tough stuff.