That was yet another strange, twisted and confusing ride.
It's clear that this anime was made by Satoshi Kon. Even though I've only seen two of his other works (Perfect Blue and Paprika), his style is instantly recognizable, fans will enjoy this.
I can't go too deep into the story without spoiling it, so I'll keep it short. The anime is about a boy who's skating around, while hitting people with a baseball bat. The show follows different stories related to the "Shounen Bat", in order to find out more about the mystery surrounding him. It does so in a way you'll also see in other works by Kon, by giving you information piece by piece, more often then not setting you on the wrong trail, forcing you to actively think about what's going on.
The animation was done well: The quality was good, considering it was a TV show, but not mind-blowing. Another note: The character design and usage of facial expressions was rather nice (If I'd have to compare, similar to Perfect Blue, but in a modern drawing style).
It took me a little while to get completely sucked into Paranoia Agent, but it did had me interested from episode one. A definite must-watch for fans of this genre!