This is difficult to rate. This game is more about art and story than it is about gameplay, but it is trying to be a game at the same time, and while I applaud the effort, it falls short. I almost gave this 4 stars, but I don't think it's quite there. I consider 3 stars "Good" (4 = Great, 5 = Excellent / all-time-best), so don't get angry ... just accept it. (OK I promise no more grief puns.)
The game is a side-scrolling adventure platforming game that briefly makes you think maybe it's a metroidvania, but it's not. You start with only the ability to move and jump, and your abilities will only grow slightly, but that's ok, it doesn't feel like it needs more. There's no spoken or written dialog in the entire game, and if you're going "didn't you say this was a game about story," then I'm glad you're paying attention because yes it is. I'm not really going to talk about the story because it is something you experience, and it is either going to connect with you, or it's not. And while I think it was well-done, it didn't really connect with me, which is fine, I can still appreciate it as art.
So what didn't work for me was two main things, and really, it's the core of the gameplay so salvaging 3 stars from that is kind of impressive.
First: the game wants you to explore and find all these hidden mementos... but if you go the wrong way you're going to permanently lock yourself out of them because you happened to randomly pick the direction of the plot. Permanently misable collectibles, especially when a huge part of the story is locked behind them (one of only a few cutscenes in the game requires all of them) is a major detractor.
The other thing is just the obtuseness of the puzzles. I've played every non-CDI Zelda including all shrines in both Switch titles, and yeah, some small % of those were stumpers, but I felt a lot more frustrated by the puzzles in Gris. For example, you may need to smash a vase to reveal something that will let you jump very high, but the vase is next to impossible to see, especially because the game likes to zoom way out at times for cinematic effect, rendering your character at maybe 1/32nd of the screen height.
So, again, is this a good game? Yes. It is worth playing? Maybe. It's short, and to a degree I can forgive permanent misables when a 100% speedrun is probably ... (actually let me google that for you... a little over 90 minutes (doesn't seem like an active category). It's free with Game Pass of this review (January, 2024), so it could be worth a try.