Love this game! Yes it deeply pushes an environmental message, but it does so in such a beautiful, artistic, melancholy way. There's an overall theme to the art, but each section has a different feel to it, with some absolutely stunning vistas throughout, and introduces a game mechanic unique to that area. Plus the fact that it really does get its message across whilst also being a really good, viable game, is a great achievement.
It isn't a particularly difficult game but that isn't its point, not all games have to be at "get gud" velocity, games are created for chilling out after all and this is perfect for that, the music complements that with soothing ambient style electronica that effortlessly switches up between areas.
The combat that official reviews moan about is ok, again, very easy and not challenging, no complex system of combat whatsoever... fine by me. It doesn't matter for this game.
Some of the platforming can be mildly challenging and it does give you a run for your money from time to time, but nothing that can't be achieved eventually.
If your gaming style is a couple of hours at night, after work, to wind down, perhaps with a glass of wine, this game is your best friend. I can see me playing this a lot (100% completion! Haven't done that for years!) it's just so peaceful and pretty. Lol. Anyways enough gushing.