Three games, one app
Buzzscraper, Bloom and Hive Heights.
Fly the gaps
Tap to stay up. That is the whole control.
Bloom
Hold to steer, and climb without falling off.
Hive Heights
Race four rivals around a kart track.
You open it and pick one of three games from a list. Each is one control and one rule: tap to fly through gaps, hold left or right to bounce up a building, or steer and boost through three laps against four rivals. You die or finish in under a minute, see your score against your best, and tap once to go again.
Toolkit: Built in Flutter with no game engine -- every game is a CustomPainter and a Ticker, about thirty lines of loop, which leaves the whole app with one plugin dependency for saving scores. The game rules are pure Dart with no Flutter imports, so all three can be run and tested headlessly. That is how the racer's track and lap timing were checked without a device.
Free, with no adverts, no in-app purchases, no timers and no account. Scores live on your phone.