It's a funny movie with the form of mockery of the silver age superhero movies, or the impression of the silver age superhero movies. Such as pretentious gestures and dialogs, ignoring the time, physics, and logics, adding on unnecessary, illogical plot twists just for the sake of plot twist, and, though acting as a gentleman, there's a wired sense of perverted coming out of batman. In short, the movie was purposely made so bad that is so good. lol
If you watch it not as a superhero movie but as a antihero movie, you will enjoy it.