I think the best puzzle games have a very simple idea that is easy to introduce but can get very challenging in the long run. Portal is a great example, and also The Witness. More traditional puzzle games like Sudoku or Minesweeper also follow this formula.

A Good Snowman is also like this. A super simple premise and small levels, but can get quite challenging. Makes you think every move, very similar to Minesweeper or chess in that sense: "ok I can't do anything else than move this here. Then I can move that one there... or this one here, but that would make it impossible to move later on... hmmm...". It has a lot of logical thinking and planning ahead (again, a lot like chess).

Overall is a very good game, great for playing a few levels when you're bored.

Now this brings a predicament. Do I rate this 5/5 because, for what it is, is perfect? Or I rate it 4/5 thinking that even though I liked it a lot and wouldn't change anything, it doesn't really compare to my other 5/5 games? I mean, this is nowhere near the leagues of Assassin's Creed Origins, but I've rated some mobile games 5/5 because they're good for a mobile game. I think it boils down to: will I remember this game later? Was my time playing it and awesome experience? No, but I do think it does what it does perfectly, it just that what it does it's not worth a 5/5, I think.