Mike Tyson in Punch-Out is definitely overly hard. The rest of the fighters are a breeze compared to Tyson. I can beat all of them, but not always in one sitting. Never beaten Tyson though.
Castlevania I just played and I don't think it's overly hard, but it is very challenging. I think the game just has enemies with very confusing patterns (how about those Medusa heads?) and not enough turkeys at parts. The jumping also needs getting used to, and jumping back after getting hit is always a pain.
