This episode marks the debut of Jack Hunter.
The candles in Cory's room are the same candle that Mary Beth lights to set the mood in the Season 4 finale.
Jack arrives as Shawn's half brother (somewhat anti-climactically). We saw a half-brother living in the trailer park during an earlier season but he is never mentioned again.
In this episode, Cory is dying for Eric to leave so he can finally have the room to himself. Cory's tune has changed since the Season 3 finale, in which Cory is devastated over his brother leaving, having felt he never got to know him.