This game costs 3,50 Euro and it took me around 15 chilled hours to play the "main missions" (up to level 19 right now). I think I never had that much fun from a game that cheap.

I also like how the game evolves over time. First you are mainly thinking about how to create specific shapes, while in the end it's all about optimization and how to get more output from your "machines".

Love it, clear recommendation!