Shells

After selecting a game mode from the title screen, you will be shown an array of crystals. Click the white crystal in the center and memorize the pattern in which the other crystals glow. When the pattern is complete, click the center crystal again to take control of it. Touch the other crystals in the same order you were shown. If you make a mistake (or if you accidentally bump another crystal), you will need to begin the pattern again. Completing the pattern rapidly will earn bonus points (you can also earn some bonus points for completing only part of the pattern quickly -- a glowing trail will appear briefly when this happens) During play, press (q) to return to the title screen and submit your score, (m) to cycle through muting the music, muting music and sounds, and unmuting, and (b) to toggle the background images on and off (in case you find them distracting). There are no failure conditions -- you may retry any pattern as many times as you like -- but your score will increase only when you complete a pattern successfully.

Memorize the sequence in which the crystals glow, then carefully repeat it while avoiding accidental collisions with out-of-order crystals. Play through 70 levels of progressive difficulty in Sequence mode, or play for as long as you like in one of three Endless mode difficulty levels.