Reef Guard

The fleet

Five rows of eleven sink together: anglerfish on top, jellyfish in the middle, pufferfish below. The fleet drifts from side to side and sinks a step every time it reaches an edge, and the fewer are left, the faster it swims. Now and then the lowest one in a column lets go a shot: a jellyfish’s sting, an anglerfish’s glowing lure or a pufferfish’s spine.

The manta ray

Every 18 to 28 seconds, while at least eight of the fleet are left, a manta ray glides across near the surface. Hit it before it leaves for 50, 100, 150 or 300 points.

Submarine and coral

It runs along the sea floor and fires one torpedo at a time: the next one can go once the last has hit something or reached the surface. A torpedo that meets a falling shot stops it. Four reefs of coral shelter the submarine. Every hit, yours or the fleet’s, bites a piece out of them, and the fleet crushes the coral it sinks into. A new wave finds the coral grown back.

Points

Lives and waves

A shot that reaches the submarine costs a life. You start with three and get one more at 1,500 points, once; when the last one is gone, or as soon as the fleet reaches the sea floor, the game is over. Each new wave starts a little lower and swims 8% faster, up to the ninth.

Controls

Move with the arrows or A and D; fire with Space, the up arrow or W, and hold it to keep firing. P or Escape pauses; Enter plays, resumes or starts a new game when the reef asks. On a phone or a touch screen, use the buttons under the reef, or hold a finger on the sea: the submarine follows it and fires. Putting the tab away pauses the game too.