Alex Kidd in Miracle World DX/Cheats

Finding the Secret Island
To find the Secret Island, players must head to Lake Fathom, upon doing this they will come across an Octopus.

Destroy it's arm by punching each segment, and then it's head and you'll be able to travel into it's pot.

This will lead you to a new maze level. Follow it to the end, avoiding the fish, and you will come to the secret island.

Underwater Spike Pit Trap
Whilst exploring Janken's Castle you may come across what appears to be an impassable underwater spike pit trap, especially since Alex floats due to his bouyancy and the game is one hit death.

Believe it or not, Alex Kidd is perfectly capable of touching those top spikes providing you don't push up in to them and surviving. Simply let Alex float gently upwards and he will not take damage from the spikes he's pushed up against.