It's not over yet, there should be one or two chapters yet to go
It says complete in manga updates tho. :( "3 Chapters (Complete)"
https://www.mangaupdates.com/series.html?id=155397
Okay, so I checked the translation team's discord and they said, " @Slow Prison Life is ending at chapter 3 (and we've known since it was announced on twitter as a 3 part series :laugh_pepe: ) Hope y'all had a good one, we sure did."
I see. Well, that's not where the novel ends. They may have decided not to turn any more into manga, but it does have a full conclusion to the story.
https://www.novelupdates.com/series/slow-prison-life/
I think it is still being updated as we speak with some neat extras
Yes, I know. The manga was made to promote the novel.
It was probably done as a mini series so that's not too surprising. A lot of chapters of novel were scrunched to make just those three chapters. I really recommend the novel because it has a lot of juicy details that were shortened to the minimum. If anything, it's even more off the rails. It truly deserves a yandere tag. I'm grateful they made it so that I could find such a great novel.
It's over? Nooooo!