Well, RM really isn't the best engine for making a sidescroller in, since you have to change practically everything. You could try asking the guy who's making that game for the scripts he uses, though they seem custom so he'll probably say no.
I would say that if you want to make a Castlevania game, use Game Maker or Stencyl, if it's out yet, or even Indie Game Maker. I don't know why you'd want to use RM really.