Minesweeper is the classic logic puzzle that shipped with personal computers for decades. A 9×9 board hides 12 mines. Every square you open either shows a number, telling you how many of its neighbours are mines, or is empty and opens up the area around it. Using those clues you can deduce where the mines must be and open everything else. It is a great workout for logical reasoning and careful, step-by-step thinking, the same skills behind maths proofs and puzzle questions in aptitude tests.
Yes. The mines are placed after your first tap, never on it or next to it, so you always start with an opening.
Long-press the square, or tap Flag mode to switch every tap to flagging. Tap Flag mode again to switch back.
Your score is 90,000 divided by the seconds you took to clear the board. You can play as many boards as you like, and your best score of the day counts.