Goofs

Joey realizes he's apparently dead because he has no reflection in the theater mirrors, but when he's in the bar and leans on the jukebox, there are reflections of his face and hand.

When Joey goes into the bar, there is a closeup of the bartender that tracks down to a whiskey bottle. The label is readable and facing right. The camera pulls back and now the bottle has the label facing away from the camera.

Though supposedly invisible, Joey's reflection is faintly visible in the theater mirror.

After trying to talk to the ticket-taker in her booth, Joey sees no reflection of himself in the mirrored wall when he turns to face it, but there is a slight, visible reflection in the glass of the booth when he turns and approaches the ticket taker again. His shadow can also be seen on the wall although he is supposed to be invisible.

When Joey steps in front of the truck, a lady screams and there's a close-up of her face. It pans out to a wider shot and, for a moment, the scream can still be heard, but the woman's mouth is closed.

When Joey is playing, it is obvious that the fingerings don't match the tune, revealing that he isn't really playing at all. At one point, he even held a valve only halfway down, which would have resulted in a very flat/bad note.

As Joey goes into the pawn shop to buy back his trumpet, there's the shadow of a boom mic on the wall to the left of the pawn shop door. And just above his head as he enters the doorway, there's a reflection of the boom operator in the pawn shop window.

Several times throughout the episode, when Joey puts the mouthpiece in his trumpet, he bumps it with his hand (causing an audible pop). This is something experienced trumpet players do not do as it can cause the mouthpiece to jam into the lead pipe, which then requires a tool to properly remove.