During the Doc Santoro assassination scene, one of the shooters gets in the back seat of the blue Jeep Cherokee driven by Butch, and before he does he drops the gun on the floor, as shown from a shot underneath the car. In the reverse angle, as the car drives away, the gun is nowhere to be seen.
When on the boat, Paulie makes food, brings up 2 plates and puts them down, Tony picks one up and says, aren't you gonna eat, and Paulie says he can't, he has an upset stomach; So why did he make a plate for himself?
When Doc' Santoro is assassinated, several female bystanders react by screaming hysterically. Even though while two male bystanders have no reaction to seeing his dead body, it's possible the male bystanders had prior knowledge of the murder was going to take place.