Er..C2 would have no problem doing something like Ghost Song. Ghost Song keeps each room in a separate layout so there aren't very many objects at any given time. There are no physics. He doesn't use tiles because terrain 'stamps' are more versatile and the better option for this type of game.
As for all the particle effects and such, Stencyl has "simple actors" for graphics and fx that have practically no overheard whatsoever. C2 might benefit from something similar, but I'm not sure a bunch of single-frame sprites will be that bad either.