This reminds me of the Twilight Zone episode (spoilers?)

The one with Burgess Meredith. It doesn't end the same though.

Some nitpicks.

Why would he use gas for a leaf blower? That seems like a waste of fuel.

He didn't need batteries. He probably should have built some sort of electrical generator with all the water (and the survivalist/technical engineering books) he had around.

Fish lived but (almost) all the other animals died?

The director seemed to be trying to create tension throughout the movie but that was unnecessary. They should have gone for the empty world schtick. Empty worlds are empty and boring. They just needed a good ending.

The end was just dumb. A false contrivance. I guess they needed some conquest but it didn't work for me.

Was the end a warning about those that are trying to be our techno-overlords, the world they are trying to create and the people they are trying to control?

Ellie is cute and non-threatening as a person. I like her. She is very much a face for her generation.

Overall, I'd recommend it but it had it's flaws. The leads drive most of the interest. If you like them you will probably like this