This isn't a complicated concept. In their short history games have seen hundreds of titles based on movies, some pleasantly good, others thoroughly confusing in their inception. To a lesser extent there have been movies based on games, not a single one of them great. From Doom to Super Mario Bros., it's all bad.
Ratchet & Clank, the 13th game in the Sony franchise since it started in 2002, is none of these things. It belonging to the rarest category of them all: a video game that is based on a film that is based on a video game.
Ratchet & Clank, a series about cartoon space people with more gimmicky guns than respect for public property, is not so full of itself to avoid the facts of its own existence. The framing of the newest game is that one character, the beefcake lunkhead Captain Qwark, learns that a film is being made based on the game based on events in his life, and decides to retell the tale, which then becomes the game you are playing. Sorry, should have asked you to sit down for that one.
With numerous nods about being a soft remake and countless cameos by characters and weapons you've completely forgotten, the new Ratchet & Clank is weirder than it is interesting. The story is a soup of the first few games put together, and the game even works in a generous amount of clips from the film. Though this is by far the best looking game in the series, you can tell when it's transitioned back to regular cut scenes, because in true video game form, characters talk with perfect posture, eyes locked with each other and standing a yard apart like in a high school play.
If the game is any indication of what the film, due later this month, is like, it seems to be largely a love letter to their own franchise, giving excited lip-service to specific goofy guns that only diehard fans might recall. In other words: I have no idea who this movie or game was made for.
The only other games based on a movie based on a game was a forgotten Double Dragon fighter and Street Fighter: The Movie (The Game). The latter was a visual makeover of Street Fighter II, with Mortal Kombat-y photos of the film's cast like Jean-Claude Van Damme and Kylie Minogue. Raúl Juliá passed away before they could record him pulling off any of M. Bison's signature moves. But that game wasn't as fun as the movie it's based on, and that film isn't as fun as the game it's based on.
This seems to be the case for Ratchet & Clank as well. It's a remade mash that doesn't taste as good as the original. So while games like these seem like they're once in a blue moon, don't feel obligated to experience them based on their rarity alone.