Revealing mistake: During the Toon Patrol chase, before the cab enters the alleyway there's a wide shot of the cab making a fast turn. Valiant has his head down, with his hat covering his face and his body totally motionless, opposite to what he looks like in the close-ups where he is grabbing the steering wheel, his head up and controlling the car, thus revealing that the actor was replaced by a dummy in some of the shots. (00:58:40)
Continuity mistake: During the alleyway chase, a trashcan on the side keeps appearing and disappearing through shots. (00:58:50)
Continuity mistake: When Valiant and Roger are in the cab trapped in the alley, the distance to the exit of the alley keeps increasing and decreasing wildly as well as the distance to the police car in front. (00:59:00)
Continuity mistake: The toon patrol car hits the 2 police motorcycles in the middle of the long alleyway, yet after they crash the cops then land in the middle of the street. (00:59:25)
Continuity mistake: When Benny the Cab approaches a bridge where the woman is pushing her baby carriage, the sun casts shadows at wildly different angles in alternating shots. (00:59:30)
Revealing mistake: When Benny the Cab jumps onto a bridge with Roger and Eddie, a red Ford De Luxe skids to avoid a collision. Notice how tire tracks from a previous take are visible on the pavement. (00:59:35)
Continuity mistake: After the alleyway scene, the cab jumps on a bridge. The first angle shows that there are no cars next to the woman with the pram, but half a second later, when the angle changes, there's a grey blue car behind. (00:59:35)
Factual error: The Goofy cartoon Roger watches in the theater was made in 1949, but the film takes place in 1947. (00:59:50)
Continuity mistake: When Maroon asks if Eddie's got the will, you can see Eddie holding his coat with both hands. When it cuts he has his arm inside his suite. (01:02:55)
Continuity mistake: After Roger interrupts their kiss in the theater, Dolores looks into Eddie's eyes and says he'd better get going. In the next shot, they're suddenly looking away from each other. (01:03:25)
Continuity mistake: When R.K. Maroon is in his office expecting a visit from Eddie, he takes a pistol and slides it about halfway into his pocket. But between shots, the pistol slides all the way in. (01:05:00)
Continuity mistake: When Eddie goes to meet Maroon with his accusations, Maroon is holding a distinctively brass colored gun. When Eddie attacks him, the gun is released by Maroon, and it instantly cuts to a shot of Eddie on top of him, an identical gun in hand. Then when they get up, Eddie tosses the gun aside. When Doom shoots Maroon through the window, Eddie dives for cover and once again the gun is amazingly in his hand. (01:06:20 - 01:07:15)
Continuity mistake: When Eddie pours out his whisky, the way he holds the bottle changes between shots. (01:06:35)
Audio problem: In the scene when Eddie goes to give Maroon the fake will, Maroon says "I'm a cartoon maker, not a murder!", when he says "Murder" his lips aren't moving at all. (01:06:35)
Factual error: When Judge Doom is at the window of R.K. Maroon's office firing his gun at Eddie, a photo of R.K. beside the armchair takes a direct hit, but only the glass frame gets shattered. Unless it was bulletproof, the picture should have been pierced right through. (01:07:10)
Factual error: At the moment R.K. Maroon gets shot and killed in his office, look at the framed poster of Pistol Packin' Possum that's dated MCMXXLVIII. In Roman numerals, two X's never appear before an L - which makes this a bogus date. (01:07:10)
Revealing mistake: When Eddie's Plymouth skids out from R.K. Maroon's lot, a large section of the Red Car's railway track gets torn from the pavement with the greatest of ease - revealing that the track is actually just a set of metal strips laid out in the center of the road. (01:07:40)
Continuity mistake: In the scene where Eddie stops his Plymouth to get out and look into Toon Town's tunnel, the passenger side vent window cranks itself open between shots. (01:07:55)
Continuity mistake: In the scene where Eddie pauses at Toon Town's entrance to load his gun, the Plymouth changes its position on the road relative to the double-yellow lines. (01:08:00 - 01:09:25)
Continuity mistake: Before Eddie drives his Plymouth into Toon Town, he breaks out Yosemite Sam's gun for the occasion and loads it with the animated bullets. The gun starts off in his right hand. But by the following shot when he gets ready to take a swig of Wild Turkey, it has instantly switched over to the other. (01:09:05)
Answer: Valiant also shares his name with Arthurian comic strip hero Prince Valiant, who wields a singing sword, Flamberge.