Bring on the tough stuff - there’s not just one right answer.
Why and how did Gregor become a vermin? Did Gregor deserve to be turned into a bug? Do you think his transformation is a literal one, or are we supposed to take his transformation as a purely symbolic one?
How does Gregor die? Did Gregor starve himself to death? Or did Gregor just lose the will to live? Or is Gregor's family ultimately responsible for Gregor's death through their negligence?
Do you think the outcome of the story would have been any different if the Samsas had been more accepting of Gregor? For example, what if they tried to understand what he was expressing non-verbally? Do you think that if they could accept his hybrid, human-insect status, they would all be able to co-exist together indefinitely?
How would the story be different if Gregor had been transformed into a different, less repulsive animal? What if only his gender changed? His race?
Take a look at the pages following Gregor's death. What happens to Gregor's corpse? Why leave it so ambiguous? And what's with the random butcher's boy?