Ok got as far as the surreal music room. No idea what to do here really. It's hurting my noggin'!
I liked the Amiga trainer splash & chip music. Reminds me of the A600 I had when I was a lot younger. I had tons (100's) of games for it bought & pirated (back when it was only possible to buy pirated games from car boot sales).
The background art is really nice. I'm not so keen on your new character design styles mind, but I think that's more of a personal preference kind of thing. I'm not right savvy on all that chibi, anime, manga, whatever stuff.
I also had issue with the elephant computer mini-game thing. I had no idea what I was supposed to do. Took me a couple of minutes to realize I needed to press the relevant arrow key when the slider entered the box on the left or the right. I don't know how you sorted out that puzzle (pure animation I'm guessing), but here's a quick tip: you could use a single animation frame & use the to() tweening function to move the animation to whatever position you want over x amount of time passed (in milliseconds) with easing. Inside of your arrow key events you would then just check if animation position is more than x & less than y to determine when to execute the required actions. Then again.. if your method works ok for you, then it works.
The English translation is ok for the most part. Few phrasing issues here & there but nothing major. I understood for the most part.
There was a few instances of the character walking in front of / behind various scene objects that I don't think was supposed to happen. Mostly happened in the living room. The character ended up walking behind one of the cupboard doors - the one where you get the present from. You need to make sure that object / image is always drawn behind the character (object center of -1). The sofa, you should adjust the way border to prevent the character from walking too far into the foreground to prevent them walking through the arm rest of the sofa.
Final point. I don't know if it was just my computer or if you intentionally set the mouse cursors to pulse & jitter like they do, they seemed to be vibrating irrationally. I'm glad I don't suffer from epilepsy as someone that does would probably be having a right field day.
Conclusion: seems ok the me so far. overall nice graphics. voice acting for protagonist & mother is fine. didn't care for the elephant voice over though. don't mind the german voice over (I'm used to watching non-english films & tv series with v.o language & english subtitles > I always prefer v.o anyway > hate dubbing). Can't really comment on the story as I've not learned much about it from the tiny bit I've played.
Anyway... good luck with rest of demo / game.