One major oversight...
If a major enemy came on the "radar" why didn't or couldn't Superman turn up? Why didn't he hear about Supergirl given that she made a few appearances in public? Wouldn't he try to offer assistance to a relative and a fellow Kryptonian?
I liked this film and thought Kara did a great job retrieving the energy sphere ;) , but I would have thought the film should have covered a major character story element beyond a few cursory references.