Continuity mistake: The number of wood slats on Baby Herman's playpen keeps changing at the start of the film. When his mom says goodbye there are eight slats at the front, and five at the side. When he escapes the playpen there are eight at the side, and when Roger realizes the playpen's empty, there are nine at the side and seven at the front. Additionally, the characteristics of the teddy bear changes, as well as the colors of the balls on the wood slats. (00:00:40)
Continuity mistake: When we're first introduce to Roger, the table on the left disappears between shots, and the pillow he rests on keeps moving closer to/away from the door randomly. (00:01:00)
Continuity mistake: When the movie starts and Herman is launched outside the park, the rattle balls on the bars disappear. (00:01:25)
Continuity mistake: When Baby Herman slides through the kitchen floor towards the fridge he stops with most of his butt on a black tile. When the angle changes he is sitting on a white tile. (00:01:30)
Continuity mistake: Baby Herman opens the faucet and floods the kitchen, but 2 seconds later there is no trace of the water. Since the rest of the mess that Herman and Roger cause (scattered cutlery, broken objects and furniture) does appear at the end of the gag when toon and real world combine, some trace of water should be seen somewhere. (00:02:30)
Continuity mistake: At the beginning when Baby Herman tries grabbing onto a clock's swinging pendulum, he stands on a box of Acme deadly mouse poison. But when the box falls over onto the countertop, its label vanishes. (00:02:40)
Continuity mistake: At some point during the opening cartoon short, Roger drinks a bottle of Acme chili sauce and flies directly into a wall-mounted ironing board. The ironing board has a handle on its left side - which vanishes between shots. (00:03:10)
Continuity mistake: During "Somethin's Cookin'", Roger lands himself in a wall-mounted ironing board. As he emerges seconds later to a barrage of sharp utensils, notice how there's a wall outlet installed just below and to the left, but it wasn't previously there when he flew into the ironing board. (00:03:10)
Continuity mistake: During the first animated Baby Herman scene, he throws away the lid of the cookie jar on top of the fridge. When the fridge crushes Roger, the cookie jar has not only managed to move from the fridge to the floor in a nano second, but also the lid is back on. (00:03:15)
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)
Continuity mistake: When Maroon says "Get me a couple of juicy pictures I can wise the rabbit off with" to Eddie, you can see him standing almost face to face with him. But when it cuts from behind Maroon he is standing away. (00:06:30)
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: Mr. Maroon talks Valiant into working for him, he has his head tilted sideways. A brief back shot shows the head straight, but the immediate front angle shows it tilted again. (00:06:55)
Continuity mistake: When Eddie is on Maroon's office pouring himself some bourbon, Dumbo shows up and scares Eddie, who throws himself on the ground. The camera then shows him and his empty glass, and the ground is dry. Where did the bourbon go? (00:08:00)
Continuity mistake: In the scene where Valiant leaves Maroon's office, he goes outside and closes the door behind him all the way. Then a cartoon character passes him. Notice the character opens the door by pushing on it instead of turning the knob? I thought Valiant closed it all the way. (00:08:45)
Continuity mistake: In the scene where Valiant gets his check notice he puts it in his left chest pocket, but when he gets in front of the trolley operator to pay he reaches in his left jacket pocket then it quickly shows him holding it showing the trolley operator. (00:08:55 - 00:09:55)
Continuity mistake: As Eddy Valiant walks out of Maroon Cartoon studios in the beginning a hippo bumps into him, then walks away. About 7 seconds later you see the hippo sit on a bench causing the bench to collapse to one side and a man fly up. You can clearly see the rope that pulls the man up as well as the actual person holding the rope. (00:09:10)
Continuity mistake: In the scene after Valiant gets rejected by the trolley operator, notice as the trolley operator is closing the door, Valiant starts to fold the check. But in the next shot, he starts folding it again the same way. (00:09:35)
Continuity mistake: When Eddie hitches a ride on the back of the Streetcar, only its rear power-arm is attached to the overhead cable. Later when Eddie jumps off and says "Thanks for the cigarettes", it has both of its power-arms raised. (00:10:10)
Continuity mistake: When Eddie first walks into the bar, he approaches Earl - keeled over on a table. Earl is wearing his hat, but one shot later the hat is lying flat on its top so that Eddie can place it back on his head. (00:11:20)
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.