Many popular games published on the App Store these days have challenges (such as "collect 10 coins in one run") to drive retention and give players more to do. The key with these challenges is that once completed, they can't be accessed again (so players can't keep completing challenge 1 over and over to gain its rewards). In Buildbox, there is a fairly straightforward way to unlock levels once the previous level was completed. However, is it possible to lock a level once it has been completed. So the level starts off unlocked, then the player keeps trying to play it until he/she succeeds, then the level locks and the player must choose some other level. Is this possible, and if so, how? Thanks!