Half-Life 2 Done With a High Magnitude of Velocity is a segmented world record speed run for (new engine) HL2, which uses this technique almost constantly. Skip to 41:40 for an instant insight into the possibilities.

In games with relatively high air acceleration like Half-Life 2, the more precise your S-taps are. the more speed you'll preserve since the longer you hold S the more you decelerate yourself while in the air. On the other hand on games like Portal wit

If you want to do accelerated back hopping on a game like Portal or Half Life 2, press the escape key when you're in the game and select options. Next, click on keyboard and select the movement called "jump." Return to the game, then hold do