Blood Pool Hall Murder Case File 2 - S2-E6
Stupidity: Even assuming that running in flipflops down the gravel road would give the culprit the required advantage over Kenmochi and Kindaichi, the culprit still had to run the elaborate setup in an absurdly short amount of time without leaving behind a single piece of gravel or wet stain (he was elbow deep in water) and hope nobody would set foot in the courtyard during the commotion.
The Death March of Young Kindaichi File 4 - S2-E4
Stupidity: The whole gimmick of this story is fun but it's pure anime nonsense; we have a 28 years guy who has spent 18 years of his life in complete darkness and malnourished. The effect of this (a stunted growth) is somewhat plausible in general, but in here he still has the appearance of the cute 10-years-old kid who was locked in the dungeon, he's athletic and a charming, fluent speaker. I don't think it's much-needed to elaborate on how that is laughable (although to be fair at least they mention that he'd light a lamp two hours a day to read and was 'exercising', which since all he ate was rats and had no sunlight at all, wouldn't quite have done him a lot of good).
The Game Mansion Murder Case File 3 - S1-E25
Stupidity: The killer's plan is rather clever, but there's a huge hole in it; assuming the killer needs to be part of the game to set up the traps, there's absolutely no reason for the person they want to -benefit - from the crime to be part of the game. In fact, it is absolutely crazy; they were not involved at all, ignoring who the victim was, and if you wanted them to inherit from the victim, you'd want them to be MILES away from the crime instead of endangering them and inevitably implicate them. If all went smoothly, the police and media would surely have been on their case for the huge coincidence; they survive a murder and inherit from the victim of said murder.
