Jurassic Park: There's a problem with the mosquito Dr. Hammond extracted the dino DNA from - it's male (you can tell by the antennae). Only female mosquitoes drink other species' blood, meaning that there wouldn't be any DNA to extract from this insect.
Movies are glimpses into these alternate Universes. We don't have superheros or time-travel in our Universe, but there are an infinite number of Universes that do. They are also different in small ways, too... Maybe that Universe had Tic-Tacs in WWII instead of M&Ms. Or, Washington had a baseball team in 1973 instead of a football team. Or, they have technology that allows them to build flying aircraft carriers AND self-resetting air bags.
Oh and Emma doesn't "bang like a screen door" she squeals like one needing oil.