My favorite movie all of all time. If you clean up the story and put some more work into the characters the idea has serious potential.
>Humans create technology that makes them an obvious threat
>a preemptive strike on humanity is launched leaving only a few survivors
>the aliens think the survivors aren't worth the effort and disregard what remains of humanity
>the survivors rebuild, deliver a devasting counterattack, and win the day
Love the soundtrack, love the character designs, love the ambiance, the atmosphere, etc.