Average animation fans may be familiar with Ralph Bakshi. After all, he was the first to make adult animation more accepted when he directed the film adaptation of Fritz the Cat.
Bakshi's career, however, began at Terrytoons. He was initially hired as a cel painter, but eventually rose up to being an animator, and then finally became a director.
So what was his earliest films like? Well, here's one of his efforts at the studio: Dr. Ha-Ha (1966). The star is James Hound, who would go on to appear in 16 more shorts.
Bakshi not only directed this, he also animated the entire film. Terry directors at the time now had the added duty of animating their films in order to save money and Bakshi was no exception.
About 30 years later, in 1996, he made two shorts for Cartoon Network featuring Malcolm and Melvin. He animated on both of them (along with Doug Compton).
Here's one of the shorts.
Notice how the style is different? If I removed the credits on both of them, would you believe that both cartoons were done by the same person?
Granted, the comparison is unfair. After all, Terrytoons budget really, REALLY decreased at this time, and massive amounts of corners had to be cut in order to make ends meet. The budget for "Malcolm" shorts, meanwhile, were more modest in comparison.
However, the change in style is still there. It's bound to happen if you work in animation non-stop for over 30 years.
Anyone have any more big examples?