This is your standard visual novel style game where most of the time you will be reading a lot of text. The game does give you choices to make and these choices can alter the story and result in you getting a different ending. Unteralterbach happens to have no single good game over. The thing is, it is so easy to get a game over and when you do, you have to go through a ton of text you have already read again.
Note that the game is way longer than most free (as in beer) visual novels I know of it took me several days to play through even one story path. So the tension is built up somewhat slow, indeed.