Good game, pretty nice design. Some of the puzzles are more 'tedious' than 'fun', and some have concepts that can be fairly easily understood- but can be problematic to implement consistently. I can't really call this a 'complaint' as I assume different people will have different approaches/understandings with different puzzles- but I really find the 'difficulty increase' to be quite off in a way that's got to be beyond that. Even so- it's quite good, and to share it for free makes most complaints without merit- though I think more people would play it farther if it's design was a more gently slope...