The rock on the dark elve planet is very strong, but it takes thousands upon thousands of tons of force to smash thru buildings like the Leviathan. Hulk slowing the momentum and bending the metal on it is better. Kurse's attack was a backhand though which is weaker than a regular punch. I'd still give it to hulk.
Hulk exerted far, far more effort, possibly pushed to his limits, while Kurse barely backhanded.
However, Hulk's feat is much more impressive than Kurse's. So far, Mjolnir has not shown to level buildings or skyscrapers with just a throw/return.
Not true at all. Hulk needed to exert himself to his limit, but he still stopped a thing which was levelling skyscrapers like a joke, while kurse didn't. We are comparing feats, not the strengths of two characters, as kurse has better feats for that.