I've got this shortly after finding this topic. The game lacks some polish in terms of gameplay. The control buttons are a bit to small, sometimes tapping the screen is a bit unresponsive. The first level requires you to destroy a number of enemies, collect a few items spawned through the area and proceed to the next one. If you haven't fallen in love with the art and music from the trailers - chances are you'll be a little disappointed. I, however, got hooked almost instantly and think that this unique feeling compensates for those few deficiencies. For me it's a piece of art, pretty rare in games nowadays. And one I enjoy, to be clear. This game doesn't compromise on the design to reach a wider audience - that's why I can understand and accept the price tag.
If you're curious of the vision the creators had - go for it, it's definitely interesting. If you're looking for an intense-action 3D shooter - skip this one, at least for now.