A good story is NEEDED (or fun if you can make it really fun). gameplay is needed. Difficlity gotta be like "you can win without savestates but it's going to be hard (and even worse if you to keep all your characters.) About characters, they need to serve a good purpuse all of them and NO overpowered characters. Portraits needs to be custom, new animations won't hurt too. Reusing characters can be allowed in a crossover WITH custom maps and events, if the characters have the same personality. Also i like when many demos comes out. that shouuld do the trick.