Thoroughly enjoy the game for it's mechanics, story, fun, and challenge.
I definitely would not call the game kid friendly as many of the puzzle mechanics are challenging enough that my partner and I, as full grown adults with multiple degrees between us, cannot solve them without many minutes spent floundering with no help or guidelines.
Another struggle I have is the game navigation. There is no map to show you progress or to jump to when re-entering the game. Which forces you to either complete whole stages in one go, or run through whole stages to get back to where you left off. The game also introduces new mechanics as you go along - which is great- however you frequently encounter puzzles requiring these skills when you do not yet have the abilities. And without a way to mark the map, it can be infuriating to try and find them again later.
Overall a fun game, but do not be deceived, it's not co-op friendly (only a few levels, which unlock as the solo game progresses) .