Wow! This really seems to be something special and it shouts "art" and "emotion" ... I probably might not resist this.

It looks beautiful!

Come on Gog . Where's the missing soundtrack DLC and bundle offer ?

I feel unsettled when seduced by a gameplay trailer for a game genre I think I won't enjoy. LOL! I blame my weakness for appealing art styles and emotionally-driven storylines. Hopefully a demo will be released. Sometimes that's all it takes to push me over the edge and into the shopping cart. Wishlisted for now. :)

A demo was published on Steam, but I have the impression that it has been removed.

It has indeed which is something many devs do after release which also confuses the hell out of me. Especially with a game that is trying something new people might want to get a taste of this to see if this is something they'd actually enjoy ... without a demo this is not possible (no, watching youtube videos is not the same as experiencing the actual gameplay). I am aware that creating a demo is costly and time consuming BUT if a demo already existed the only reason to remove it would be if you aren't satisfied with it as a dev ... but that is unlikely since there is a reason you even released the demo in the first place. It also might be that the released game is even better - no problem here as well, simply add something like "demo does not represent final product" like so many others are doing. Just don't remove the demo.

Hit-and-run game demos confuse the heck out of me too. Either release one or don't. Like you said, a simple disclaimer should do the trick. GOG's recent Spring Sale had an entire page dedicated to demos, so this gives me hope that there is a demand for them. :) Fingers crossed for Lost Words!

This game looks so beautiful! ^_^

Maybe it's a lack of confidence.
They may think that the demo is enough for some players to occupy an afternoon, and then spend their money on another game.
Personally I like to own the demo of a game I like, it can allow me to give it to a friend to encourage him to buy the game.
And I hate it when GOG deletes my demo from my library, when I buy the full game!