By the way. Yes, there are several more "survival stages" and different enemies and interactive stuff (fans, conveyors, moving platforms, etc.) a few stages ahead of the point where you left it.
I updated the game emphazising the double jump mechanic on the third stage. So thanks again for giving me that feedback.
Finally. Hard mode difficulty is more challenging for experienced players. I made a "normal mode" to make the game more accesible with a soft difficulty curve.