once you get into the actual puzzles, solve them for yourself and do not use a walkthrough!

This one... requires... a lot... of... patience... and... waiting... :P
Seriously. Anyway... go to the right and you'll notice what looks like a
stationary cloud. Believe it or not, it's actually moving to the left VERY
slowly. It takes a good 2 hours for it to complete its journey to the left.
You'll actually want to jump on it at about 1 1/2 hours into its journey. It
should be just above the first door next to the cannon. This is where you want
to park Tim, waiting for the cloud. You can't do anything to speed up the time,
so I suggest you have a controller that doesn't turn off automatically for this
to work (otherwise, the game will keep pausing when your controller goes off).
At any rate... once you're on that cloud you've still got about 30 minutes left
to wait. After it finally reaches the left-hand side, you can jump up and onto
a ledge just above you and to your left. Notice that a new part of the level
is revealed. You can now nab that star you waited so long for. Congrats!

Some of the puzzles will be hard. But when you manage to solve those hard puzzles, you will feel very good about it. The game will feel very rewarding. Don't rob yourself of that feeling by reading a walkthrough!

He has also said that he "would not be capable" of explaining the whole story of the game, and stated that the central idea is "something big and subtle and resists being looked at directly."