Disney's Bolt is based on the movie of the same name. The movie (according to Wikipedia's summary — I haven't watched it yet) is the story of a dog that plays a superhero in a TV show, who is accidentally mailed across country and must make his way back to Hollywood.
Rather than playing out the plot of the movie, instead the developers chose to dive deeper into the TV show fantasy world. You play as both Bolt the super-dog (with his TV show superpowers intact), and as Penny, his owner and the daughter of a kidnapped scientist, as they try to rescue said scientist from the evil super villain.
The gameplay alternates between Penny, who uses sneak and stealth, and Bolt, who pounces on bad guys in a much-simplified hack-n-slash style.
The game is fairly simple. As Bolt, the majority of your play is attacking enemies by jumping up and pressing X and/or Y to attack, repeatedly. Once you hit an enemy enough, a "B" button icon floats over their head, and if you attack with the B button, you will grab onto them and can then press any of the four buttons to do a "finishing move".
As you progress, you'll come across enemies that are resistant to the basic attacks, and you'll have to use one of Bolt's "special powers" to stun or weaken them first. Most of the time, your first encounter with each of these will have a single instance of that enemy and plenty of on-screen tips to help you learn how to defeat them (although one particularly frustrating segment on a train introduced a frisbee-wielding maniac that seemed unstoppable, with no on-screen tips, until I happened to catch a random loading screen tip that gave me a much-needed suggestion for dodging and returning his discs).
The difficulty ramps up by throwing more and tougher enemies at you at a time, which makes the game simple, but rather repetitive.
Penny's segments are much more low-key. With no health bar, one attack means a restart. She has the ability to go invisible, giving her the power of a "sneak attack", and if she is caught, a quick-time-event button press comes to her rescue. Fighting and avoiding enemies is the minority of her tasks, though; she must spend more of her time navigating the terrain. Finding where to go is made easier by an "enhanced vision" mode, which highlights "interesting" paths in yellow.
Penny also occasionally comes across computer terminals, that she "hacks" in a minigame very reminiscent of a few Xbox Live Arcade shooters — left stick moves, right stick fires. Move and destroy everything in a 2D playing field, without getting destroyed yourself, and the terminal is hacked.
It's a very simple game, with very easy to learn controls. Some platforming parts can get frustrating, as can some of Bolt's fighting sequences when the game just wears you down with the repetitive flow of stronger enemies. There is, however, very little consequence for failure, as the game simply restarts (often fairly close to where you were), and you try, try again.
It's also a fairly long game. For a movie tie-in, there's an extraordinary amount of original content (probably having to do with the fact that it's not trying to recreate the movie). There are lots of environments, and the cutscenes and in-game voice acting are pretty well done. The game is fairly well polished. Although there are some areas that are difficult to get through due to questionable environment structure, the game is completely playable with almost no game-breaking bugs or even destructive camera controls. (My son did seem to come across one moment where Bolt somehow got into one of Penny's mission areas, where the only way out was to "suicide", but the game recovered gracefully on the restart.)
Achievement-wise, most of them are straightforward, pretty much unlocking themselves as you play the game. The "Max out health/power/gadget bars" require finding and collecting all the upgrade items along the way — most of those are easy to spot, but if you're not using a walkthrough, it's easy to miss one or two. And there are a couple others that, while they may not be entirely self-evident, are easy enough with either a little planning or a simple guide.
All things considered, it's really not a bad game. It may not be terribly exciting, as the bulk of it is fairly repetitive, but at least it doesn't feel like your typical "movie-to-game" game.