[eNotes editors are only permitted to answer one question per posting.]
Kafka's The Metamorphosis has several themes. The first is alienation. This theme is demonstrated with regard to how isolated Gregor feels going out to work everyday, and coming home to a family that has little regard for him other than that of bringing in money to support them.
The next train left at seven o'clock. To catch that one, he would have to make a mad dash...And even if he caught the train, there was no way to avoid those storm clouds brewing over the boss' head, because the firm's errand boy would've waited for the five o'clock train and reported the news of his absence long ago.
Gregor struggles over "father-son antagonism." It becomes obvious that Gregor's father greatly resents his son. When he can no longer earn a paycheck for his family, his father becomes aggressive and violent.
He had filled his pockets from the fruit bowl...and now, without aiming precisely, threw apple after apple. These small red apples rolled about on the floor as if electrified and bumped against one another. One weakly thrown apple grazed Gregor's back but slid off harmlessly. One direct hit that flew immediately afterward penetrated Gregor's back; Gregor wanted to drag himself a little further, as if the unexpected and unbelievable pain would go away with a change of position, and yet he felt like he was nailed down and stretched out, all his senses being completely confused.
Betrayal is another theme. While Grete is originally very supportive of her brother, this changes when Gregor can no longer earn a living. While he is closed off, Gregor is unable to work; his dad gets a job, Gregor's mother takes in sewing and they do their best to meet their financial obligations.
Escaping is yet one more theme. As Gregor becomes a gigantic bug, this may only seem to offer a means of escape: while Gregor was out working each day, he could not understand the need for him to slave away each day in a job he detested. Whereas Gregor wakes from unsettling dreams, he may actually not be an insect at all, but simply be experiencing feelings of isolation. And so Gregor's sense of isolation may not be real, but simply a means to escape a reality that he finds too horrific to endure any longer.
Seizing power is a last theme. When Gregor turns into a bug, and the family goes out to find work, his father is the first to take on a position. He wears a new suit, combs his hair and gets himself dressed each day. He goes out to earn what money he can; and Gregor finds that his father had some funds hidden away. Gregor is relieved by this situation, proud that he was able to provide for his family for so long. Now he feels a sense of pride that they are doing so well. However, before long, Gregor's sister Grete takes control at home. She becomes the leader in the family. Here we see a combination of betrayal and seizing power: Gregor's father drives the disrespectful roomers from the apartment and Grete passes judgment on her brother: he must be gotten rid of.
“Dearest parents,” said the sister as she struck the table with her hand as an introduction, “this can go no further. If you perhaps don't recognize that, I recognize it. I will not pronounce the name of my brother in the presence of this monster, and will say merely this about it: we must be rid of it.
Ultimately, the family agrees to do so, and move on with their lives.