This is Simon Tatham's open-source collection of 40 single-player logic puzzle games ported to Android. It will always be free with no ads and playable offline.

See the screenshots for the full list of 40 different games. They're all generated on demand with adjustable size and difficulty so you'll never run out of puzzles.

Various control options for small screens: on-screen arrow keys (can be enabled in Settings) pinch to zoom and a button to swap press/long-press.

Beta testers welcome! Join beta tests with the button on this listing.