Alien Mahjong

Three levels is the whole of Alien Mahjong, and bestphysics uses them to teach one unusual button. The pieces show aliens, robots and laser guns, they come off in identical pairs, and a piece is selectable only when a left or right neighbour is missing. So far, ordinary enough. Also under this heading: the Sweety board.

Bomb mode is the departure. When the board has no legal match left, the bomb generates new matches instead of merely rearranging what is already there, which means a dead layout is never a lost one. It is also the only tool the game hands you, so the question across the three levels is when to spend it — at the moment you are stuck, or a few moves earlier while there is still a shape worth improving. Directly alongside it sits the Jewel Quest board.

The set is drawn large and flat, and the 990 by 660 board expands to full screen without the sprites going soft. It plays on the desktop machines that make up most of this site’s traffic and on touch devices, where a tap does the same work as a click. A neighbour from the same shelf is Valentines Mahjong Deluxe.

1. Match two pieces carrying the same alien, robot or laser gun.
2. Check that the piece is not boxed in, because one of the left or right sides must be open.
3. Clear every piece in the level to move on to the next of the three.
4. Trigger bomb mode when no matches remain, since it generates fresh ones and reopens the level.

• Bomb mode is not a shuffle — it creates matches that were not there, so it rescues a board a reshuffle could not.
• Strip the ends of rows — a piece with a free side is worth more than a tidier pair stuck in the middle of a locked row.
• Save the bomb for level three — the first two layouts are usually solvable without it.
• Watch for triples — with three identical robots showing, clearing the wrong two can bury the fourth.
• Full screen suits this board — the sprites are drawn large and hold up when the window is stretched.