Plot hole: This series is in the same continuity as the other Marvel animated series that aired around the same time - X-Men, Spider-Man, Iron Man and Fantastic Four - by virtue of each aforementioned show crossing over with at least one of the other shows. However, the origin of the Leader in this show is inconsistent with his origin in Iron Man. In the Iron Man episode "Hulk Buster," which originally aired on February 10, 1996, Samuel Sterns became the Leader after a barrel of gamma waste fell over and spilled its contents onto him. In this show, which didn't air its first episode until September 8, 1996, Samuel Sterns became the Leader after he sabotaged Bruce Banner's gamma bomb test and fell into a pit of radioactive waste caused by the bomb. Rick Jones' role in Banner being exposed to the gamma bomb is different as well. In Iron Man, he parks his jeep in the test area and casually plays a harmonica. Here, he is riding his motorcycle through the test area and crashes, and is unable to restart his motorcycle in order to get clear of the blast.
Character mistake: Throughout the series, General Ross refers to Gabe Jones as Gabriel. Someone of Ross' military credentials would not address another government agent by their first name. He would call him Agent Jones or simply Jones.
Answer: The Hulk is a giant brute who smashes everything in his path when he is angry. In Ang Lee's "Hulk," General Ross, played by Sam Elliot, explains it to his daughter.