This series was brilliant, but really the last one kinda dissapointed me. There were like two pieces of evidence leading to the culprit and there were several plot holes.
The grammar was kinda poor, but I loved the writing style! The dialogue tags varied unlike some children's books I've read and it gave you a theme.
Conner seemed.... dunno if you were reading that without knowing how old he was you'd think he was a middle schooler.
The jokes were terrible and it kinda felt a bit crazy that even the adults were watching Daniel and the Celler Dweller's videos and laughing at it. It's middle school humor, but I doubt most eight graders would be laughing at that.
Mina's personality changed a lot. Her reply to Daniel's text seemed off to her personality. She's shy and a bit of a creepy stalker and the way she texted him just seemed... not right. The words she used didn't fit in with her personality. Not consistent.