HOLDHold to open. While the water covers you and your shell is open, you feed and grow a ring.
LET GORelease to close. Closed, nothing can reach you. You feed nothing, but you are always safe.
GULLA shadow crosses before it stabs. If you're open when it lands, you lose a little food.
CRABA ripple gives away a crab before it pinches. Open costs you more food than a gull.
WAVEA shadow rises from the water before a wave slams the rock. Open when it lands, and it takes you. Closed, it never can.
RINGSEvery warning comes early. Watching is the whole game — your rings are the only record that you did.