What it’s about?

Paul Rudd plays Scott Lang, an expert burglar with a masters in electrical engineering.  Scott has just been released from prison.  He can’t get a job and he is estranged from his daughter who he loves dearly.  Scott is trying to go straight but it seems impossible – until the mysterious scientist Dr. Hank Pym, played by Michael Douglas, shows up.  Pym has created a suit that enables a man to become ant-sized.  You can imagine the possibilities of that.  The Ant-Man suit also enables him to telepathically communicate with ants of various shapes and sizes.  Eventually he and his ant-army take on the evil villain who wants to sell these miraculous minimizing suits to evil organizations like Hydra. 
What works?
The best thing about Ant-Man is Paul Rudd who is the most unlikely superhero.  His laid-back charm and ordinary Joe quality make you root for him.  Ant-Man is co-written by Edgar Wright who was originally supposed to direct the film.  He stepped away citing the usual creative differences and Peyton Reed stepped in.  But there are flashes of Edgar Wright-style eccentricity and fun.  The climax with a giant Thomas the Engine has real energy.
What doesn’t?
I suppose it had to happen.  After years of creating thrilling blockbusters, the mighty Marvel Empire would deliver an underwhelming superhero.  Ant-Man lacks personality. Reed doesn’t give it a signature.  Moments of genuine humor are flattened by long passages of banal exposition. The film retreads familiar tropes. It feels like an aside, an insubstantial placeholder until the next giant, inter-galactic saga comes along.
Should you see it?
If you are a sucker for superheroes.