Jenny Slate is awesome. The rest of the cast also does a good job with how little they were all given. This essentially is a pretty light story, not every story needs to be Avengers Endgame, and it does a good job allowing character development carry the day. In the end I just was left wanting something a little more.
From reading other reviews, I think MacFarlane in casting the lead role to MacFarlane vastly overestimated the audience's tolerance for his smug face saying smug lines. I honestly think he may have cast himself just for the chance to make out with the smoking hot Theron a couple times. And if so, then bravo.
I didn't laugh as much as I wanted to, but I shut the brain down and had a good enough time with it.