Your goal is to survive as long as possible without colliding with shapes other than your own.

Once you consume enough of your shape, you can shift up to new shapes. (See Controls)

At any point, you can shift back down to shapes you were before. See the left panel for your current shapes.

Controls:
Arrow Layout:
Movement: Arrow Keys
Shift Up: A
Shift Down: Z
Reset: R

WASD Layout:
Movement: WASD
Shift Up: Up Arrow
Shift Down: Down Arrow
Reset: R

Xbox 360 Controller:
Movement: Left Stick
Shift Up: B
Shift Down: A
Reset: Start