Question

after ripto beat the video games last level, he didnt know what to do with his spare time.
keep the comma
remove the comma

Explanation:

The opening clause "After Ripto beat the video game's last level" is a dependent adverbial clause that comes before the independent main clause "he didn't know what to do with his spare time". A comma is required to separate an introductory dependent clause from the independent clause that follows it.

Answer:

Keep the Comma