Melina's fistfight with Lori. Stylized, yet brutal and edgy.
Quaid fistfighting the Robot Captain. Particularly in the Director's Cut. The fight intentionally avoids stylizing the fight, and concentrates on straightforward, raw attacks. You almost feel the sting whenever the robot punches Quaid in the face/ribs.
During the elevator shootout, Lori runs towards the elevator that Quaid and Melina fled into as it descends and slides through the open elevator shaft right on top of them.
The Fall itself: a skyscraper-sized elevator that shoots through the entire planet at impossibly fast speeds, complete with momentary gravity loss as you pass through the earth's core. Completely implausible? Sure. But as the setting for gunfights? Awesome.