I am on the first dungeon, the Dragon Roost Cavern. I made it through,..

In the shrine were medli gave you the grapling hook when you get out, you land on a small floor then go right until you find a door, enter. When you enter you'll see a bridge and some bad guys there, kill them and cut of the bridge, when you fall down you'll see another door and a chest, open the chest and you will find a joy pendant. Open the door and you will find a big cage with ropes in the center, charge a spin attack to cut them and wait to get down. When you get down jump into the plataforms and you will see a door with a dragon-like mouth on it, in the roof you will see a thing to use the grapling hook, use it and the door will open. You will find a room with a big chest sorrounded by flames there will be scorpions there, make the scorpion be a roll and place it on the swich, and the chest with the boss key is yours

Peace

There's this one door that's in a giant mouth, you need to face the middle of the room and Grapple the Switch on the ceiling to unlock it (check your Map to see where you haven't been). Go through the door, Grapple the next Point and head to the path on the right by using the R-button to slow down and change directions. When you get to the next room, you'll need to hit a Magtail (Centipede) so that it curls up into a ball, then pick it up and put it on the Switch to get at the Boss Key from the Treasure Chest! Hope that helps =D