Experiment: ZEN mode now has random level progression

This is an experiment. I like it already, but I'm not sure where to plug it in. This is my current solution:

If you change from CHALLANGE to ZEN mode (use new slot/delete current). Then after reaching the goal you are teleported to a random level that you could reach with the currently collected coins. So, instead of using the coins to jump to a higher level, you are automatically jumping to a higher level, but random. That way, each run would be different, and: without complicated coin-level-handling you get automatically to the higher levels fast.