Superman realizes it’s too good to be true. If Krypton had survived, the populace would have followed him into space to become Supermen like him. At the very least, he’s certain his father would have come looking for him.
Brainiac appears and explains that he recreated Krypton in order to lure Superman away from Earth and drain him of his power but the recreation is a little too perfect. Superman finds an adult-size rocket prototype and escapes Krypton’s red sun long enough to recover. Nevertheless, Brainiac wins by forcing Superman to witness the destruction of Krypton firsthand. Clark returns home to mourn for the first time knowing what he’s lost.