A very nice hack overall. You have the aesthetics down packed in each level.
You should work on the info box's grammar in the intro.
For the first level i have to disagree with the musical choice. It just doesn't seem to fit the level. There is also a lack of power ups. Only one mushroom and it's pretty obscure to find.
In a few levels you have layer three and it disappears when you reach the goal. Just create a pipe to a room w/ out layer three. Cold cave looks good. Make sure to add a power up here and there. Some of those jumps look tight.
@mamlazizou: Actually it's a vanilla layer 3 BG, so that's why it's a bit simplistic (although, you can easily change it with the latest version of lunar magic).
By the way, this hack has a french thread, feel free to speak french there.
This overworld looks nice, despite of the perspective issues that Wormer21 pointed, but I think you can fix them easily. There are also some missing "lines" here and there, but that's not something very important.
Other than that, it's very varied. Good job!
I accepted the demo but I would still like to see some improvement on the slow down issue due to too many sprites.
Here's a few examples.
Koopa beach near the first set of Venus Fire traps
Torpeshi pretty much most of the level
Deciduous Forest same pretty much the whole level but is really bad if you get the flying wiggler guys chasing you.
Making a hard hack is fine but there is a big difference between being challenging hard and just hard due to sprite spam.
I will also add that is was quite fun to play and very well put together, besides the slow down, and if you want to keep the peach coin instead of the dragon coin just go into GFX01 and edit the half a yoshi coin their to make the the sprite status bar match the actual coin.