I've been recently playing Verlet Swing recently, fits here perfectly.

I'll add it! Though this is missing a lot of titles I just haven't thought to add.

Would also like to suggest games like Pizza Tower, The End is Nigh, and even Hollow Knight (that last one may seem weird, but it actually has a couple of achievements that actively encourage completing the game as fast as possible)

Speedrun achievements would balloon this list to unmanagable proportions IMO. Beating the game quickly is a relatively common achievement for games and doesn't really get at the core idea

a few suggestions:
- Post-Void
- Ape Out
- Anger Foot (full version not released yet but the demo is a similar kind of high speed FPS - you can even drink energy drinks to speed up the game)
- Gonner & Gonner 2 (platformer / run&gun rougelites with a combo mechanic that encourages speed, and a soundtrack that speeds up as you get combos)
- Slow Mole ("8-bit platformer for the NES that makes everyone a speedrunner")

Katana ZERO needs to be here. It unlocks a speedrun mode after you beat the game.

Added!

only just started playing but RAYZE fits this to a tee. all abt making quick movements nd building up speed by making big combos