7-5 is a rather annoying level -- if you don't have the Propeller Suit, that is. There are tiny clouds that blow fog at Mario, and it becomes hard to see where you're going. You can spin to get rid of the clouds and fog.
The first part of the World 7 Castle is shown in this video. I actually found the Castle to be rather challenging at certain points. The conclusion of the World 7 Castle, including the boss fight against Ludwig von Koopa, will be in the next video.
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