While the plots are different, Sakurai Sho plays in both of these dramas as very similar characters. Both characters are eccentric and have very similar mannerisms and catchphrases (Iiii neeee~ vs Nantsutte~) and both have dark secrets they are hiding. If you liked Sho's character and acting in one, you will enjoy him in the other.
The main role is Sho Sakurai he acts like a psycho in both dramas, except that in Kazoku Game he wants things to get better using his crazy somewhat violent ways, but in The Quiz Show 2 He is a host in a LIVE TV Quiz program, that asks the contestants questions of truth not knowledge and due to an accident he has lost his memories.
Both psychological dramas, both deal with manipulating other people into looking into themselves and may be changing for the better. Both have a cute and crazy lead character with a past. :)
They are both suspenseful dramas that keep you guessing throughout. Food for the brain along with chair-gripping mystery.
Both are dramas with the same kind of psychological game show format where people have to face themselves and their true selves are revealed to the public. Both involve a complicated connection between the characters that is revealed over time. They also have the same kind of pacing and the villains remind me of each other.