I think you’re getting stuck on the “game over” part. This by itself does mean “the end of something” But “start over” is a separable phrasal verb that means “to begin again”. So you can say “Let’s start over” or “Let’s start the game over”.
I always felt a little bad for ESL students who just discovered phrasal verbs because they’re basically a whole new set of often nonsensical verbs to learn.
If you go by what my high school teachers taught me, grammatically the phrase should ‘technically’ be “start over the game,” but nobody speaks like that.
I say this because there are plenty of grammar “rules” that nobody follows that are still taught in schools. I don’t know if ESL students learn them too, but if they do it’s gotta be hella confusing
I think it’s an obligatorily separated phrasal verb. This page has some examples of others like it https://random-idea-english.blogspot.com/2013/04/phrasal-verbs-that-are-always-separated.html?m=1
