When you are next to the town fountain press 'A' to deposit coins and unlock the following effects in the game when the indicated amount is reached.

Unlock 2 Extra Lives:
Deposit 200 coins.

Unlock 5 Extra Lives:
Deposit 500 coins.

Music Available 'Special':
Deposit 1,000 coins.

Palette available 'Horizontal':
Deposit 2,000 coins.

Music available 'City Funk':
Deposit 3,000 coins.

Stamp Available 'Shape2':
Deposit 5,000 coins.

Unlock 10 Extra Lives:
Deposit 6,000 coins.

Music available 'Alt.':
Deposit 7,000 coins.

Unlock 20 Extra Lives.
Deposit 8,000 coins.

Unlock Developer's Grove (Town):
Deposit 10,000 coins.

Unlock Invincibility:
During gameplay pause the game and hold L and press A, X, B(2), Y.

Unlock Full Health:
During gameplay Pause the game and hold L and press Y, X, Y, X, A.

Unlock 5 Lives:
During gameplay pause the game and hold L and press X, Y, B, A(2).

Unlock 30 Ammunition:
During gameplay pause the game and hold L and press B(2), A(2), X.

Unlock Alien Templates:
In Draw mode hold L and press X, Y, B, A(2).

Unlock Sports Templates:
In Draw mode hold L and press Y, A, B, A, X.

The Robot, Animal and Plant templates are unlocked in 'Draw' mode by holding L and entering the corresponding code.

Unlock Robot Templates:
Press Y, X, Y, X, A.

Unlock Animal Templates:
Press B, B, A, A, X.

Unlock Plant Templates:
Press Y, A, B, A, X.

If you throw 10,000 Rapo coins into the town well you will be able to switch between Normal and secret town when you want by tapping the wishing well at the bottom of the screen with your stylus.