It wouldn't have been good in color. The shadows they have through the film give it the feeling you get from the old movies of Frankenstein and Dracula. Gene is great as he kicks the older man and then sticks the scalpel in his leg and also yells about his grandfather's work.
All of the colors and music gives the cartoon feel. With the "good guys" "bad guys" we see the whole Dudley Doo-Right show. With the good guy wearing the white suit and the bad guy in black is how the cartoons were too so you knew who to root for. The scene made you feel like you were in the past with the costumes. The rocket and balloon are homages to the old slapstick and some of the over exaggeration.