Yoshi's Island: Super Mario Advance 3 Cheats

Grab a Melon Bug (the creature that rolls up into a ball) and go to the pipe with Shy Guys jumping out of it. Spit the Melon Bug close to the pipe on the left-hand side. When Shy Guys jump out, after a while you will get a "1-Up" for each time a Shy Guy hits the Melon Bug when it is in its melon form.

In any World, whenever you get your World Score to 777, you will earn 7 lives.

After you have gone over all the hills there is a pipe that ‘Shy Guys’ come out of. Ignore them and go past the pipe and get rid of the Killer Plants in the next two pipes to the right (one above and on the ground). A Kooper is walking between the two pipes on the ground. Jump on the Kooper and send his shell spinning between the two pipes. ‘Shy Guys’ continue to jump out of the pipe on the left and every time the Kooper shell hits them you will hear a different sound that means you’re getting lives! Stand on the pipe on the right and the lives will continue for as long as you stay on this screen.

Beat the game to get a whole new set of 6 levels not found in the original Yoshi's Island.

When entering the arena, do not pass the end of the stone colonade that is at the very edge of the large arena room. This will allow you to see the small pirhanna plant without activating the boss battle.

From here, you can fire an egg at the pirhanna plant and destroy it with one hit. This forces Kamek to appear and say 'OH MY', before fleeing. Having already destroyed the plant and scared Kamek, you will not have to fight the Naval Pirhanna, thus avoiding a potentially difficult boss battle.

Simply beat the game 100% and the next time you boot up yoshi's island the game's title screen will show yoshi's island but it will be night instead of day