A Passage for Trumpet - S1-E32
Revealing mistake: Joey cannot see himself reflected in The Mirror. However when he walks past the booth, he has a clear reflection.
A Passage for Trumpet - S1-E32
Audio problem: When Joey steps in front of the truck, a lady screams and it shows a close-up of her face. It pans out to a wider shot and for a moment, you can still hear the scream, but the woman's mouth is closed.
A Passage for Trumpet - S1-E32
Continuity mistake: When Joey goes into the bar, being invisible, after pouring himself a drink, the bottle rotates on its own accord.
Answer: It's explained in the episode. The aliens are experimenting to see how humans react to various scenarios. This just happens to involve them using super strength.
Thanks. It's been a long time since I saw the episode so I forgot.