Update Feb 2026:
This feature is very basic: It picks levels apparently at random and gives levels a harder label by removing a few moves. If you pick the harder version you gain some timed rewards after passing, even if you retry the level several times. Removing moves makes some levels slightly harder to pass, but other levels are just as not affected by this at all because for many levels the number of moves does not actually affect your chance to pass. So choosing the harder version may give you a level just as hard/easy as choosing the easier version.
This popped up in my new account today, shortly after reaching level 200. This is the weirdest and maddest thing I have come across yet: We can choose if we want to play the "harder" version of the coming level:
Naturally being inquisitive I had to try this out. Especially since I currently have two accounts both sitting at the same level. Account 1 did not see this feature, so played the normal version (rated super hard) of level 207, account 2 chose the legendary version. I just had to see if they would be different!
The two starting boards looked pretty much identical:
Both started with the fish and super charger combo. But the legendary version has fewer moves! And well, I failed:
Unfortunately to retain the super charger I had to not only pay 10 gold for extra moves but also play a UFO. Serves me right for being so nosy.
The other version passed easily:
Well I won't be doing that again! And nor will anyone else who has their head screwed on the right way, I should think. Whatever are they thinking with this stupid feature???