I'm not sure if it's still true, but for a while this game had zero negative reviews on Steam.

I'm quite far in now, but I think there's still a while to go. The game purportedly had 300+ puzzles.

More than anything I'm really enjoying how comprehensively the rules are explored. There seems to be every permutation of rules used in a puzzle somewhere and the number of different 'rules' or 'ideas' that it gets out of a relatively simple premise is pretty staggering - probably more than most sokoban games I've played.

On that note, I'm really enjoying the glut of quality puzzle games recently. The Witness, Stephen's Sausage Roll, anything by Alan Hezelden (Good Snowman, Cosmic Express, monsters expedition), Bonfire Peaks, Pipe Push Paradise, Baba is You, Recursed and more. It's a good time to be a puzzle gamer.