The art leaves something to be desired, but that's not what this series is about. As much as I love the Kindaichi series, I always feel like it reaches and contrives. This spin-off properly makes fun of those contrivances. It's great and hilarious.
First time I read a manga that shows the perspective of the MC's enemies (villain of the story). I thought it would have the same atmosphere/feeling of the original series but this is totally the opposite. This makes me think that the original one is also as hilarious as this one, only that we can't see it coz it's gonna be funny from the side of the culprit. I haven't finished the main series but this totally changes how I view it from now on.
@Teddy
The first chapter of Hannin-tachi Jikenbo, which was the Opera House case, came out on 12th July, 2017. The schedule for the next releases has been irregular. The Japanese releases are uploaded to this site, each chapter has a disclosure time of 30 days. If you click on the individual chapters, you'll get the dates on which it was released.
https://pocket.shonenmagazine.com/episode/13932016480029113180
P.S: Sorry for the slow updates, will pick up speed soon^^