When Doomsday first charges, he runs across the lava Superman is level with, tut Superman's flying through it revealed the bottom to be a good ways below the lava's surface, so Doomsday could not have walked on it and should have been submersed. See more
Whatever you think you're doing, if you present a threat to the world, the Justice League will take you down.
If we present a threat? You've got a space ship floating over our heads with a laser weapon pointing down! In another dimension, seven of you overthrew the government and assassinated the President! We're the good guys, protecting our country from a very real threat: you!