Short, simple, rewarding puzzle game that is both conceptually very cool and that also has a great difficulty curve; the early game tests basic concepts and things gradually ramp up from there. I found the final two puzzles to be particularly challenging and an appropriate pay-off for all the groundwork covered up until that point, making me have to really sit and rethink the situation several times over but leaving me feeling very good when I finally understood what those puzzles were trying to communicate and got to the desired solution.

Took a little over an hour to complete, with about a third of that time being spent on the final two puzzles.