Note: This review contain spoilers for the episode. You have been warned.
I wish that the whole season could have been as engaging as this one. It has some surprising new developments on the multiple killers front, as well as some surprisingly fascinating insights into the minds of the characters. I think that the new trend in this season of starting off the episode with some narration by a recurring character vastly improves the quality of the show. Not only does it show their point of view of the events, it also expands their characterization. In this case, Dr. Holt narrated the opening, showing the deeper struggle that he has with his replacement hand. It came from a serial killer and he can hear the voice of the former owner, taunting him. Yes, it's that kind of show. The hand cartoonishly taunts him, keeping him awake and stressing him out. The more awake he is, the more he longs to kill.
Speaking of killers, Chanel No. 3 actually finds out that Dr. Cassidy is one of the Green Meanies. This not only causes an interesting conflict in their budding romance but also strains his already-uneasy alliance with Hoffel. I genuinely liked the character developments in this episode. It had a good balance of seeing how everyone reacts to the tense situations and cases.
In terms of humor, it's finally back to the point of manageable idiocy. It's just implausible enough to be wacky but also grounded enough to keep me invested in the plot. A highlight of the episode featured S.K.H. (Serial Killer Hand) saving Dr. Holt from one of the Green Meanies through inexplicable kung fu action. Additionally, S.K.H. tortures Dr. Holt and keeps him from sleeping by forcing him to watch religious telethons at ungodly hours in the morning.
Zachary Krishef is an evil genius. Do not question his knowledge of Saturday Night Live trivia or Harry Potter books.