The cut above Danny's left eye disappears in some scenes.
After the ring is set-up and Flynn is shown training in it, the next scene has him and his manager under the stage with the ring in the background being not set-up. Two scenes later, the ring is back up.
During the televised boxing match in Londonderry, no TV cameras are
seen around the ring area.
In one of the early scenes when Danny meets and talks to Maggie, she slaps him on the left side of his face. It was a very weak slap yet he gets a bad nose-bleed - from the right nostril. In the boxing sequences when his face is pummeled, there is less blood.