Brothers is a totally competent puzzle-platformer. You pull levers, climb ledges, and use both brothers to open doors. Mechanically, it's fine. My hands started to hurt after a while, but let's chalk that up to design issues with the 360 controller.
The art is very pretty, but it suffers from a case of the generic art style blues. You could quite literally swap out the art with any other fantasy game, and it would work perfectly fine. It looks nice, but doesn't have enough style of its own.
Worst of all, the storytelling is in an awkward gap between a full-fledged story like Zelda and an implied story like Journey. I wasn't attached to any of the characters, and a twist towards the end of the game was so bizarre that I was put off until the game ended.
It's probably worth playing Brothers, but it's certainly not game of the year material.