@ceosol, out of curiosity, what do you mean by "infinite shadow clones"?
Say you move right to jump on a platform but it is too high. Rewind to before you were jumping and a clone will appear going along your previous path. You can then jump on your clone that is attempting the jump. But say this jump still isn't high enough, rewind a little bit more and a new clone pops out, jumping on the first clone. Then you have two clones that you can use. Keep rewinding and you could fill the screen with clones.
The first thing you might think is that the game framerate would drop to zero. This may be true. What I would like to prototype is passing the clone instructions to each individual having them running autonomously. This should decrease the amount of resources required to keep track.