The point of the game is to collect all circles and advance levels. Use the on screen D-PAD to move LEFT, RIGHT, UP and DOWN (helpful if you are in water).
Be aware of spikes (dark ones and yellow/red ones) and enemies (green moving thing). If you touch one of them you lose at least one life out of 3.

Use pumps (green/red body with yellow top) to increase or reduce the size of the ball in order to fit in places where you normally wouldn't.
Use trampolines to jump higher (only works if the ball is normal size, not reduced).

Use platforms to move around but be careful: jumping is disabled on them.
While in water there are currents that will drag you up possibly in spikes. Control the ball by using DOWN on the D-PAD.
Roll below the blue arrows to save a checkpoint.

After you finished collecting all circles (check the HUD at the top of the screen x out of y collected) you can search for the door. If it's red (closed) you haven't collected all circles or coins, otherwise the door will be open, allowing you to complete the level.

The game might be hard but it's not impossible!

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