Wave-dashing - Super Smash Bros. Melee
For a confusing, silly, knockabout mascot-fighter, Super Smash Bros. Melee has a Hell of a lot of nuanced, high-level technical tomfoolery going on. Because Super Smash Bros. is made of physics. And physics, more than maybe any other element of video game design, is potentially a festival of exploitation.
There are a bunch of maneuverability exploits, such as L-cancelling (to reduce recovery time after landing a jump) and short-hopping (as the name suggests), but the undoubted king is the wave-dash. By air-dodging toward the ground at a sharp angle, players discovered, entirely by accident, that it’s possible to maintain the dodge’s momentum horizontally along the ground. Smash characters are now able to moonwalk forward or backward, attacking in either direction with the full compliment of their stationary, ground-based move-set. Unsurprisingly, within months, wave-dashing became the technique to learn for tournament-level play. Though Nintendo didn't seem to like it, and took it out of Brawl. Booo!