Two characters connect by a rope is not really new.

Maybe have a read through this: http://en.wikipedia.org/wiki/Knuckles'_Chaotix

I have this game at home and well... it is chaotic. The physics get out of control from time to time and the level design is pretty confusing. This was the major problem of the game. All levels looked the same in some way.
Not sure if it is good to follow this way - also the basic concept should not be changed THAT much anymore after it has been chosen from various ideas.