It's an app, yes, but it's not one of those 'typical meh storyline games'. It's honestly really good and interesting, very well-thought-out. Pixelberry's stuff is great. The only thing that irritates me is that you need diamonds (either bought or take a while to earn) for some choice options and it really sucks when there's one that's your first choice or the smartest one plot-wise. But even with that it's a great game, and if you buy diamonds it at least funds decent developers.
Be warned, it's quite addicting. xD