I really enjoyed this episode because it feels like a payoff to a lot of the character behaviour that this show has been building all season.
It was also great finally meeting Sheldon's twin sister properly. Watching this after Young Sheldon makes her appearance even more interesting now because she later becomes a much bigger part of that world. The second Missy walks in, the entire group completely loses their minds, and honestly the reactions are hilarious because they fit each character perfectly.
The biggest standout for me though was Raj and the experimental medicine storyline. Some of his scenes absolutely killed me, especially seeing him desperately trying to bypass his usual social problems in the weirdest way possible.
This episode just feels very TBBT in the best sense – awkward, nerdy, ridiculous, and really funny throughout.
A very enjoyable episode overall. 7.5/10.