There are secret rooms in 1-2, 1-4, 5-5, 6-5 and 7-3. In 1-2, go to the room with the Needle Ability. To the right of the room, there's a Maxi Tomato. In the place you find the tomato, fly to the top left. There's a hole with a secret inside. 1-4, go to the end of 1st room to the edge of the screen, then backtrack. You'll see a hole that wasn't there before. There's a door, enter it. 5-5, In the 1st room, climb the tower, don't enter the door, fly higher. Enter the barred door. 6-5, Go to the end of 3rd room (Rooms include crushing stages) where Halcandran Waddle Dees fall off the conveyor belt. Climb the conveyor belt until you reach the dead end. Enter the hole in the net-like background. 7-3, Go to the goal room, but don't enter the finishing door. Fly directly up to the meteor in the background. Enter the meteor.
Added by: EmeraldDragon1128 Jul 31st 2012, ID#5256