Thank you guys so much for those comments. It really keeps me motivated.
I also finished another level - this time it`s the first one of the game. In this level, Rayman starts looking for Globox in an area inhabited by teensies. Globox was captured (once again) earlier by pirates that are already busy taking over everything. The hoodlums appear in the second half of the game.
Aaand by the way, I now have a running grenade as a new enemy!

A small place with a little river that you can follow trough the cave. AND HEY, LOOK AT THOSE PRETTY LUMS!

The pirates reached this building before we did. And yes, the shotgun shells at the right will be redrawn too.

Awww no, help comes to late for those teensies.

Here we are in the mines that lead to the exit. Also, spot the pirate!
And here we have an EPIC FAIL that I didn`t even notice as I built the level.

I still have no idea how I couldn`t notice that all the time. I finished the level yesterday, saved it, opened it up today and was greeted by a mirrored swastika in the middle of the level. I don`t have the nerve to change the entire level architecture because of this, so I leave it and hope the player won`t notice (and if, I hope that the player has enough coolness to take it

).
@spiraldoor
I already tried that, but there is one problem. The color palette that the engine uses doesn`t get along with blue und greenish colors (that this sky texture uses) at all. After I imported it, it looks like a total mess. I already recolored many other textures I used, but in this case it`s hopeless. I could, however, convert the sky texture to grayscales, which looks a lot better. On the other side, the engine only allows three skies, each of them used in ten levels (the original game had 30 levels). And the sky texture I have now fits very well to the surrrounding of my first ten levels (where the pirate stronghold also appears) so I will most likely keep the sky I have. But I already thought about using a different sky texture with a similiar look, because the one I have right now looks a bit too blurry.