Journey

Games where the route matters more than the destination. Most here are sliding puzzles where getting one piece to an exit means moving everything else out of its way first.

Unblock It 3D. The goal is visible immediately - one marked piece, one exit - so the difficulty is entirely in the solution rather than in understanding what is being asked.

No, and that's the point. They're built for thinking rather than reacting, so a board will wait indefinitely while you work out which piece has to move first.

Vikings: An Archer's Journey is the outlier, taking the theme literally with distance to travel and archery along the way rather than a board to solve.

Yes, all of them run free in your browser with nothing to install and no account needed before you start, and none of them limit how many attempts you get.