A frustratingly not-terrible action thriller.
Based on the video game franchise of the same name, "Ratchet & Clank" makes a concerted effort to undermine and joke about the common, generic elements of its story and its characters. It's filled with establishing subtitles, naming some alien planet and then subtitling the subtitle with, say, a countdown to the dastardly villain's inevitable speech that will lay out the details for his wicked plan.
We get a training montage, of course, but it's preceded by a sub-subtitle informing us that one is on the way. During that scene, the unlikely hero gets a chance to test out all of his nifty, new weapons. Eventually, the leader of the team runs out of neat-sounding names for all the cool weaponry, and he's reduced to calling one of them, which fires a sawblade, something along the lines of the "killer buzzing thingy."
The movie's attitude is commendable. It's actually trying to have fun with material that should be fun, and it's also actively making fun of the pieces that are worthy of mockery. It's as innocent in its approach to all of this as a movie that features the destruction of several planets can be, too.
The effort is often obvious, and that means a good number of the jokes are funnier on a theoretical level than they are on a practical one. That's one issue. The other major one is that the humor only goes so far. At some point, the movie has to rely on the things at which it previously poked fun.