Given the large number of levels in the game, our design team spent a lot of time considering how to sequence them. We started by assigning the levels a difficulty value. We took into account such things as level size, number of different mechanics used, and number of rotations needed to finish the level. Then, we held several playtest sessions where we observed people playing the game. In particular, we noted where players hit speed-bumps, i.e. they stopped being able to progress as easily. Finally, we dropped the difficulty every time a new mechanic was introduced in order to ease players into the mechanic, and also to give them a sense of improvement.

Based on our observations and the players' feedback we finalized an appropriate difficulty curve for the game. In later playtests, players were easily drawn in by the game's seemingly simple mechanics, then as we ramped up the difficulty they became more invested to get to the next challenge. We also added a system where the next three level were always available, so if players got stuck they could skip to a new level.