It was a good fight, but I realized Death Battle may have forgotten something.
A major factor of Shin Godzilla and Ultima is their ability to adapt their bodies, developing new powers and abilities. Ultima can even see the future in order to pre-adapt.
So if Banner was allowed to use the extended time the fight took to solve the equation, why wasn’t Godzilla allowed to use his extended time to adapt a power to counter the Hulk? For example, a hyper-precise heat ray that hits Hulk’s brain and causes brain death while not actually killing him so he never goes through the Green Door? Or an adaptation of Godzilla Earth’s forcefield that traps Hulk and leaves him unable to move or escape? Or a Gamma Radiation absorbing organ that depowers Hulk by sucking all of the radiation out of him?
Might not have been enough to change the result, but seems like an oversight.