Geometry Dash

Geometry Dash is a one-button reflex platformer where every obstacle, jump and gravity flip lines up to the beat of the level's track. You guide a small geometric icon along a side-scrolling course that auto-runs forward, tapping at exactly the right millisecond to clear spikes, saws, walls and the occasional rocket section that swaps the rules entirely. A single mistimed press resets the run, which is the entire point.

The official level set is built around the soundtrack, with each stage's difficulty pegged to how aggressively the music wants to kill you. Practice mode lets you plant checkpoints anywhere on a course to grind through a section without restarting from zero, and the icon and colour customisation is mostly cosmetic — Steam players get two exclusive unlockable icons on top of the standard pool.

What keeps the game alive years after release is the built-in level editor and the catalogue of user-generated levels stacked on top of it. Players have produced thousands of tracks, ranging from beginner-friendly remixes to demonic, multi-minute courses that only a handful of people have ever cleared, and the editor itself is robust enough that most of the famous community levels rival the official campaign in production quality.