To beat the last level, you just need to make your clones jump off the cliff. Whilst in the air, keep on pressing (spamming) the up button, while holding on to the right button. That's not all, once you disappear into nothingness, continue to press the right button for like 5 seconds. What this does is, if one of your clones manage to step on another clone in the air, it will jump again, and it will reach the other side. But you'll have to walk to the door after that, thus continue the right button for a while. Well if you r lucky, it might be you instead of your clone who manages to step in mid-air for another boost to reach other side.