Archie and the painting
At the end of the movie Archie has the painting...how did he get it? If he violently stole it from the Russian then that scene should have been important enough to show in the movie. Leaving out that scene is a big hole in the movie's continuity. Before we see Archie with the painting we assume that the Russian has his painting back and is free to go on to pursue other business. But because Archie got his painting we don't really know what happened to the Russian. It's an untied loose-end.
Maybe that scene was dropped in editing?