Twinsen's Odyssey Cheats

Walk to the citadel on the first island and you'll see a cow standing there. Step behind the bovine, press and hold the X key at its rear and then press and hold down the forward arrow key. This will make the cow drop infinite clover leaves.

On Zeelich at the Island of the Wannies you will see, near the village, a frog on a leaf in the lava. You can jump on an other leaf and kiss the frong when you press ACTION.

On Otringal there's a dog training course with obstacles. You can complete this course yourself, although it might be a good idea to get rid of the dogs first.
Also, you can do action of the dog houses for a trick or a treat, so watch out.