This game was really something special. I can't say I've played a game recently that combined unique mechanics, eye-pleasing imagery, creative scenarios and emotional impact in quite the same way.
I read some reviews that said the game mechanics were nothing groundbreaking, so I can only speak for myself – I've personally never played a game where you can control two characters in this kind of control scheme before, and I thought it was really cool. I've played games where a single player has to control two characters cooperatively, but not where each of your hands controls one character, essentially. It was easier to get used to than I thought, but I noticed how my brain got a little scrambled if I accidentally put big brother to the right of the screen and little brother to the left and tried to make them move in the right direction with the opposite hand lol. It was a new and interesting experience for me.
The puzzles were fun and I thought the single-player co-op idea was used in an innovative way – while there were the basic scenarios like having one character pull a lever to give the other character access to an area, or having to control each oar separately to steer a rowboat, there were also more unique ones like having the brothers take turns decoying and distracting an enemy while the other runs to safety, or carrying both ends of a long object and trying to navigate it through narrow spaces. Scenarios that two people working together might face in real life or in a TV show or movie but that you don't see as much in games (at least not where you're controlling two separate characters at the same time).
The fairytale-esque world the game takes place in was also really delightful. The environment was used well – they could have just had all the obstacles be fallen trees or rocks or similar predictable things but I didn't quite expect to have to move the bloody corpse of a 1,000-ft-tall giant out of the way. And I liked how in addition to having the brothers cooperate you had to cooperate with various NPCs as well, like the troll thing that throws you places and stands across a gap so you can walk across its shoulders.
All that said, the biggest thing for me about this game that I will probably remember forever is the relationship between the two brothers and the climax and end of the story. Before I get to the spoilers, I really loved how the cooperation directly played into the strengths and weaknesses of each brother. Maybe the little brother (Naiee) being able to fit into small spaces and the big brother (Naia) being strong enough to pull big levers is predictable, but the fact that you have to have Naiee hold onto his brother to swim because he's afraid of the water, and how that plays into the backstory, was different and kind of touching. I also like little details like how there's a big horn randomly in part of the game and when Naia blows into it it makes a loud sound but if Naiee does he can't blow hard enough lol.
Onto the spoilers ...
The climax and final scenes of this game are the most cruel, crushing, heart-shattering, devastating emotional gut-punches I've experienced in a game in a long time, if ever. I was mentally begging for a cop-out, I didn't care if it was a cheap, cheesy "It's a miracle!" ending where everyone lived happily ever after. But we didn't get that and not giving us that was probably the right decision because ... phwoo.
The very concept of having to control little Naiee dragging his brother's corpse into a grave and burying it ... no words. There's a somewhat adjacent scene in a playable part of Homestuck (not the same scenario or context but draws a similar emotion) but the Brothers scene beats it by about a mile. Game-wise, it's a very simple task, it's not challenging at all. The challenge is psychological. It's something that you don't want to do, but you know you have to – just like Naiee.
With the sheer shock of the twist, and the build-up of the game investing you in the brothers' connection by focusing all your efforts on their cooperation, the raw emotion I felt at the end of this story is something I only get once in a blue moon from a video game. Not to mention, if the burying scene doesn't get to you, the part where Naiee can only swim on his own when you press Naia's action button will have you bawling.
Overall, this game was great for me even without the emotional storyline, although I will say, although there was enough variety in the puzzles to keep me interested, it could be pretty easy at times. I only died a handful of times, so if there's something negative I could say it would be that it's too easy.
But the story and emotions and deeper connection between the gameplay mechanics and the essence of the plot really did it for me. This is another game that's leaving the Origin Basic vault in a couple weeks so if you have Origin Basic, I highly recommend it. Regular price (on Steam) is about $15 and I would say it's worth that much if you want the emotional experience but not so much for the gameplay if you want something that's exciting and challenging. I'll also note that it's a pretty short game, I finished it in about 2 hours (but just sort of went straight through doing very little extra).