Extraordinary. They did what Community people do best: surprise, connect, impress, and leave the audience both wanting more and eager to re-watch the entire 70 episodes again (now 71 with the finale) now knowing what's going to be connected with what later on (e.g. the keytar, and the deceased twin).
Brill from beginning to end, and I'm glad it was not predictable (IMO) and ... there really are no words to describe how outstanding it was... I loved it.