I guess it's impressive just that there's enough opponents around to push you to that limit as the norm.

Mmm, well... replicants were declared illegal and not allowed on earth, and Deckard's job is as a cop who specializes in 'terminating' replicants. He'd tried to get out of the force, but forced back in to chase four of them who'd hijacked a ship and come back because they're trying to find a way to extend their lifespan -- they were made with a built-in time limit.