TilePuzzles.com

The site opens directly into a puzzle - no splash page, no account creation, no tutorial pop-up. You arrive, there's a wooden tile board in front of you, and the objective is printed underneath: 'Move the large square tile to the bottom left corner.' The game just trusts you to figure it out.

With 40+ puzzles across multiple difficulty levels, it goes way deeper than it needs to. The Klotski-style boards where you maneuver a large block through a maze of smaller ones are the real draw — simple rules, but you can sit on one for ten minutes and still not see the solution.

The 'Impuzzibles' section is introduced as 'possibly the hardest tile puzzles on the net,' and the site has been here since 2002 - long enough to have earned that claim. The Tile Championship leaderboard invites you to submit your hi score, which implies someone is still checking.