While the game is fairly good (it has a lot of obvious potentional), I do have some (mostly minor) complaints.
First, there's no in-game instructions for how to interact with a character. It's mostly just poor design not to have that.
Second, I got all three endings in about four playthroughs.
Third, there's no indication that "hey once you exit, that's the end of the game". At the very least, add a message after the end screen saying "THAT'S THE END OF THE GAME FOR NOW" - or an ability to click on the icon to bring back to the main menu.
Overall, I did enjoy the game (though I wouldn't call it a demo - it felt very much early alpha compared to an actual demo; while the game works without any game breaking issues that I could find, I felt it had a bit too little content to be labeled a demo).
I am looking forward to the full game, should you make it. Like I said, it seems to have a lot of potentional.