Delve is a free daily card puzzle about surviving a dungeon. Each room shows four cards. You take three, and the room refills. Clear the whole deck before your health hits zero and you win.
No. The first time you play, a short animated how-to walks you through the rules and your first move.
Yes. Past days open from the week strip on your results screen.
Yes. It runs in your browser with nothing to install, and you don't need an account.