In the last scene in police station there is a calendar saying July 2015, but this movie is set on true events in 2007.
At 25:35 Mairead offers the customer another fish head. The customer says "It's a salmon head". It is definitely NOT a salmon head! :)
Conor's room features an Eminem poster from his 2013 album even though the movie is set in 2007.
1:04:14 Ray the Drug Dealer limp to bike boys without dummy shoe.