Continuity mistake: When Solo begins trying to seduce the dancing girl with the line, "We shall taste paradise," he's standing at least a foot away from her. But in the very next shot, they're suddenly in a clinch: her hands are on his cheeks and they're about to kiss.
Continuity mistake: At the end, Solo and Illya are sitting at a small bistro table as the captured bad guys are marched past them. Solo wears a green fez, and between shots, Illya suddenly acquires a red one. It wasn't in his hands or on the table before that: it just seems to appear on his head out of nowhere.
Factual error: Posing as an art collector, Solo tells the Re-collectors that he owned a valuable painting looted 20 years ago by the Nazis during the war. Improbable at best, and oddly, they don't seem at all curious as to how the 30-something Solo might have afforded such a treasure when he'd have been 12-15 years old at the time.
Continuity mistake: Delgado's plane makes a bumpy landing (without a runway) and skids to a stop in the Brazilian jungle, surrounded by palm trees. But when everyone gets off, the plane is suddenly parked in the midst of an industrial compound with buildings all around it, and no palm trees in sight.
Plot hole: Bad guys tie lousy knots. Solo's bonds at the end are so loose that he easily slips his feet free to stop the swinging blade. And the rope across his chest does nothing to pinion his elbows or lower arms. He could have reached up with his hands to catch the blade at any time.