Players have the ability to save the levels they've created, upload and publish them. They will receive a unique 8-digit code for every level to share with other players. Users can either load the levels into their treehouse by accessing the terminal in the underground and entering the codes or by finding them in the level browser (only if they're published). Levels can be saved locally and online from within a game by using the Pause menu.
Most custom levels are built by placing custom level parts and other blocks in a blank level in free play mode.
Level Loader[]
The Level Loader terminal has five tabs that offer different sources for loading levels. The leaderboards for the fastest challenge mode times can be viewed here. Players can also favorite, save, share, report and vote on any custom level through this interface. Only the host of a lobby can access it.