If you're expecting something like 'The Untouchables' you're going to be disappointed. Ruben Fleischer's (Zombieland) comedic roots really helped make this film different. It's certainly a lighthearted film, it doesn't take itself seriously, which is nice to see. It does bring with it a very good gangster film though. It may not have the most unique concept or the most developed characters, but it's certainly enjoyable and entertaining throughout..
It really is testament to the director that he got the casting so right. Ryan Gosling - who I consider to be this generations Marlon Brando - has got his cocky, charismatic, ladies man down to a tee and Sean Penn has got his villainous mob boss perfect too with some fantastic hints of comedy that lighten the mood. Josh Brolin - the Captain America of the group - has to assemble a squad to take down Sean Penn. In doing this, he just happens to choose the most stereotypical group of people you could find. The Avengers they are not.
However, it certainly relies far too much on all out action and mindless set pieces. I would have loved it if it could have been slightly more intelligent about how it went about it's action pieces.
All in all though, Gangster Squad is bold, brash and exciting. It's not what you're expecting, but it's an enjoyable film with an excellent style and fantastic performances. It's brought crime films into a new era and I would love to see more films of the same ilk.