I updated the initial post with a newer video and progress... It keeps me focused on the project...
I'm currently working on a parallax scrolling script for the ending sequence... which works quite well now...
The game is nearly finished. The playing part is completed. The missing parts are character animations and the ending sequence, so it's entirely playable...
I'm considering asking for help to alpha/beta testers (whatever state it is, now) here on AGS forum. But, as I don't plan to make an english translation before it's finished, it would require french speaking testers... and I don't know if there are many here.