I saw GRIS in some YouTube video or another, thought it looked unique and decided to give it a try. And the initial impressions were quite encouraging: the art style is really unlike other games I've seen and the music is pretty nice too. Unfortunately, that's about where the positives end.
GRIS seems to take some inspiration from the Metroidvania subgenre, but misses the mark completely: there's no map (and the game's pretty confusing at times), the power-ups are very basic and you never backtrack to explore where you previously couldn't. You just keep running to the right (or sometimes left) through rather empty environments (whose unique art style gets pretty monotonous after a while, largely due to a very limited colour palette), do some platforming and sporadically solve a simplistic puzzle, and that's it. There are no enemies to fight or even hazards to avoid; the best you get is a huge bird that knocks you back by screaming, but that's just a puzzle to be solved, not a boss fight as you might expect.
On the technical side of things, at least GRIS runs very well, with no crashes and a stable performance. For some odd reason, though, the game doesn't let you map any of its controls to Num5, which is a problem to me, because I use the numpad instead of the arrow keys for movement. Also, the weird camera, with its constant zooming in and out, doesn't help any.
Overall, GRIS had some potential in the art department, but squandered it completely with its gameplay. And I just now realised I didn't even mention the story, which goes to show how much it mattered. Suffice it to say, I played the better part of the game without encountering much of it, finally gave up during the underwater level (where else), checked the ending on YouTube and decided it's not something worth enduring the entire game for. Give it a pass, unless you can get it really cheap so that you can take some nice screenshots to put on your wallpaper.