When Richie shoots Bobby outside the market, he throws the Polaroid pictures on his body. There is lots of blood on Bobby's shirt. When Gino shows up to investigate, the shirt is obviously less bloody.
When Gino encounters Richie for the final fight, we see Richie coming out of the bathroom, holding a gun on his head. The white cup in front of the lamp is gone, but was visible in the previous shot.
When Detective Felino first offers his badge as a 'trophy' to Sammy for anyone who can take him, the badge is in his right hand and his gun is in his left. In the next shot, his badge is in his left hand and a bar towel is in his right hand.
Detective Felino never picks up the bar towel that he turns into a blackjack by putting a cue ball in it; it is not present in one shot and is then present in the other.
When Gino takes the roller away from Richie, you see it in Gino's right hand as he pushes Richie through the window. The scene cuts to Gino, who flexes his arms to show his right hand is empty. Another cut to Richie attacking Gino, who once again has the roller in his right hand.
Geno is a Narc Detective in a Brooklyn precinct but for the entire movie he's basically worked homicide tracking down and avenging his partner's killing he would have not been allowed to work a homicide case and that isn't his unit total fiction..
When Gino confronts Ritchie's dad in his own home, he looks down at the floor to make sure he hits his (very visible) mark.
Just before he fights with Richie, Gino grabs Tattoo's arm, pulls him through the railing and slams him face-first into a brick wall. When Tattoos hits the brick wall, it moves.
After Richie visits his brother's bar, an overhead view shows his henchmen stepping away from their very visible marks on the floor.
When the mobster's confront Richie's brother for the last time as they leave him sitting on the pool table their marks are (again) clearly visible on the floor.
When Gino hits Richie with the roller, the padding on Richie's back can clearly been seen underneath his shirt.
When Gino enters Richie's hideout in the final conflict of the movie, he is carrying a single pump shotgun, which requires a pump per shot fired. Upon entering the kitchen he consecutively shoots three different people without pumping (loading a shell into the chamber) the shotgun once.
When Gino shows his wife the puppy and asks if they should show it to their son, she responds, but her lips stay closed.
When Richie and his cadre escape Gino, he is looking all around in the passenger-side seat while saying, "Let's take him out for some pork chops." But it is not in sync with how his mouth is moving.
During the car chase you can see police barricades set up and onlookers watching the filming.