[@FinalFrog]To answer your question, the characters were only strong in their respective games. In the crossover verse, which is a separate dimension that Platform City exists in, all the characters start equal. The NPCs, however, are treated stronger than the usual characters because they are supposedly experienced. However, if you decided to play Alucard then that would change for more OOC, game-balance reasons than story reasons.

If your character acts villainous, which I say villains aren't playable, then the heroes will probably make his time in this game short. As you figured, they are still heroes.