When Water and Power capture Rebecca, Kesslee asks how many of his men she killed. The captain says 8. She actually killed 9: 1 with the grenades, 2 just after that, 3 by the bridge bit of her home (2 on it, 1 under), 2 more when the Water and Power plane landed, and one after the 'oil change' scene.
When Tank Girl and Jet Girl are hiding out with the Rippers, all of the Rippers have large, kangaroo-like feet. In the final battle scenes, they're all wearing normal, human-sized shoes. During the cartoon ending, Booga has large, kangaroo-like feet.
The Tank alternates between having a silver machine gun and not having one. The gun alternates between an Uzi 9mm and a 40 caliber. It looks physically smaller after Tank Girl has "fixed it up", and its size changes constantly.
At the prison, Tank Girl says that she doesn't want to miss "Baywatch". And later she says to Jet Girl that both of them can go to New York and see the musical "Cats". In the year 2033, both Baywatch and Cats will be very much outdated.
Near the end, when Rebecca and Kesslee are fighting, she kicks him off the platform. When he lands with his cybernetic arm trapped in the gear, his real hand is visible through a large gap in the fake hand.