Continuity mistake: When Jessica appears on stage, Eddie has Betty Boop standing next to him in all close-up shots, except for a wide shot of the public behind Jessica where Boop is missing. (00:18:15 - 00:19:05)
Trivia: When the taxi Jessica and Eddie are in hits the lamppost, she spins around and her dress shifts position. For a couple of frames on the laserdisc version her underwear vanishes, or at least it appears to. Opinion is divided as to whether it's a deliberate move by the animators or just an error in colouring. (https://www.snopes.com/fact-check/who-stripped-jessica-rabbit/). (00:18:15)
Revealing mistake: When the weasels are at Eddie's apartment and Roger is handcuffed to Eddie, Roger runs under the bed and drags Eddie on the floor. As he pulls him you can clearly see a board with wheels under Eddie that is pulling him under the bed. (00:38:50)
Visible crew/equipment: When Roger and Eddie get in a truck and there's no key, Roger hears the voice of Benny the Cab in the back of the truck. He then slides through a little window and his love letter to Jessica pops out of his pocket. A black glove can be seen pushing this letter through the window. (00:55:15)
Revealing mistake: Close to the film's climax, when Doom is showing off his Dip Machine, we see one of the weasels hoisting a canister of Dip up a ladder. If you look close, you can see a large wire pulling the canister up. This was seen in the VHS version and may have been corrected in the DVD, I am unsure. (01:19:20)
Continuity mistake: When Eddie Valiant is in his office, and he examines the newspaper photo of Jessica Rabbit and Marvin Acme, the picture doesn't match the photos shown to RK Maroon earlier in the film, and neither does the original of the photo he looks at next. The photo shows an earlier, less sultry version of Jessica, in a halter-neck dress. (Jessica wears a strapless dress throughout the film). The DVD's Toontown Confidential special feature mentions that Jessica's look changed during filming, and the scene where Eddie takes down the Jessica photos and looks at the holiday photos of him and his brother was re-shot to show the new Jessica. Looks like they either missed the newspaper scene or felt that the view was so brief it wasn't necessary to change it. (00:35:49)
Visible crew/equipment: In the alley scene, where the two motorcycle policemen collide with the police car, and the motorcycle cops fly over the car, you can see the landing pads placed on the pavement to cushion their fall. (00:57:05)
Continuity mistake: In the scene where Roger and Hoskins are moments away from crashing into a bridge in the cab quickly look at the road there is no gate in between the roads. But when they jump onto the bridge they crash right into a gate. (00:57:15)
Continuity mistake: At Maroon's office in the beginning Eddie is holding a newspaper. The way he holds it changes between the shots. (00:06:10)
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)
Deliberate mistake: The window blind in Maroon's office changes to a sheet of tambour (as found in roll-top desks) just before Roger crashes through it. This was to ensure his outline remains perfectly in it, otherwise pieces would drop out which are not attached to the strings on either side. (00:23:25)
Visible crew/equipment: Right before Eddie goes in for a closer look at the will in Marvin Acme's patty cake photo, a boom mic is reflected in the magnifying glass. (00:36:15)
Continuity mistake: When Mr. Acme meets Eddie at the joint, he squirts the magic ink at him. The position of the things on his table keeps changing between shots. (00:15:45)
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: In the office of Maroon, Valiant gives back the paper to Maroon. The next shot he is holding it, but in the next shot its in his left pocket. (00:06:45)
Continuity mistake: When Valiant walks out of the garbage and reaches to a window in front of him, the box and bottles next to it change positions between shots. (00:21:45)
Continuity mistake: When Angelo is messing with Eddie you see Angelo holding an egg. When Eddie grabs him you can see the egg is suddenly peeled. (00:12:55 - 00:13:05)
Continuity mistake: When Roger jumps out of the chair and through the window in Maroon's office, you can see the glass shatter with jagged edges at the bottom and no clean outline of Roger. The next shot shows the glass cleanly cut in Roger's shape. (00:25:00)
Continuity mistake: When Eddie hands Roger the patty cake photos in R.K. Maroon's office, they look cluttered. Cut to the next shot and the photos are suddenly stacked neatly. (00:23:05)
Continuity mistake: In Valiant' office notice the whiskey bottle to the right of Valiant. Then Roger is about to sit in his brother's chair. While Valiant is yelling at him, look right in front of him the whiskey bottle is there, but then when he sits down the bottle is back at its original spot. (00:39:15)
Answer: There's really a lot of possible reasons he hates other toons. There's a whole Roger Rabbit book and comic book series that explain Doom's background more. In the film, he's greedy and wants to destroy Toon Town to build the freeway to make more money. In human disguise he's also seen as merciless and is just punishing toons to maintain law and order, etc. Although that's just an excuse to kill toons as well. However, not explained in the film; as a toon he was cast as the antagonist in cartoon films until an accident one day left him thinking he was an actual villain (as opposed to just an actor playing one). That's when he began his life of crime, including killing Teddy Valiant. So his hatred of toons is more about him being evil and not a personal vendetta against them, like Blade's motives.