As of the end of the show, this is Glee's highest rated episode on IMDb with a rating of 9.6/10.
When Rachel gives Will the plaque with Finn's photo and his quote, "The show must go on...all over the place...or something," Will asks her if Finn actually said that. She laughs and says yes. This is an actual Finn quote from the episode 17 in season 2 "A Night of Neglect."
There are some notable absences in this episode. Despite Quinn Fabray (Dianna Agron) having a strong connection to Finn Hudson (Cory Monteith), Agron was not asked to be back for the tribute for unknown reasons. Brittany (Heather Morris) was also not present as she had given birth shortly before shooting.
Though the cause of Finn's death is intentionally brushed aside in Kurt's voiceover, there is an allusion to Carole's speech in which she confesses to Finn that his father died of an overdose, and that one moment of his life did not define him--very similar to what Kurt said about Finn.
The episode starts out with the gang singing "Seasons of Love" from Rent which stared Idina Menzel who also happens to play Rachel's biological mother.