Rayman Designer Demo - The caves of Skops 

In the demo version of Rayman Designer, it contains 4 levels. And all of them are not in the full version of the game.
THIS must be the hardest level in the demo! Here, you have to get on the cloud while avoiding tons of obstacles and collect all of the tings. There are no checkpoints in this level. So if you lost a life, you'll spawn all the way back to the start.
There is an unused level title for the caves of Skops in Rayman Designer called "Cloud of Doom". So, this must be that level.