A great game!
Level design is very well organized and directed. Nice progression that keeps the game fresh during the whole game session. Not sure if the box thing was a puzzle or you just needed to activate all levers tho.
Controls are very well implemented with enough looseness to have the right amount of difficulty.
Nice music selection, but I would have choose a different music for some situations like when the builders fall.
Sound effects well implemented also. maybe the sun made a sound that give the sensation of a buggy and unfinished game, which is not the case.
Art is very cohesive and appealing. Interesting effects that improved the experience such us the use of lighting, the parallax effect of the beginning, the camera vibration of the builders falling to name some.
Very good job!