Super Mario Run

Super Mario Run is a fan-made side-scrolling platformer in the classic mould, not an official release. You run to the right, time your jumps over gaps and enemies, and try to reach the end of each stage without losing your footing.

Platformers like this come down to one thing: committing to the jump early enough. Most failed attempts are half a beat late rather than badly aimed, and once you stop hesitating at the edge of a platform the stages get noticeably shorter.

Controls are arrow keys or on-screen buttons, and it runs in the browser with nothing to install and no account. Levels are short, so it fits a few spare minutes rather than a long sitting.