I have such problem: when I was level 3 I made a map. It was parkour map with interactive fiction. Some days later when I was level 7 I decided to play this map fo nostalgy(and for 100/100 rating). When I loaded map I was able to jump over the walls and... umm... "hack" this map. The reason is I was more skillful at level 7 than at level 3. I am sure that it isn't only my problem. I hope that you will fix it. For example, you can temporarily decrease player's level. For the other hand, then level will have no sense. Anyway, I am not good at making ideas. =/
 "Ultimate Crab Battle"){kind=icon}
 "Sandbox Hero"){kind=icon}