The term "state of the art" is much over-used in computing, and you should rightly feel sceptical when it is used without thought.
I have thought for quite a while before deciding to describe this game as a state of the art offering.
My reasons for giving it such an accolade are many, but basically it comes down to this. I have never seen a better thought-out and executed game - nor am I likely to see such an original idea for some time to come.
The aim of the game is the obliteration of various types of alien. I've heard this before, you say, but wait.
The aliens appear in an excellent three-dimensional representation before your very eyes. You can move in four directions while they dodge and weave in front of you.
The effects - both sound and vision - are most realistic, and the game can even make you feel motion-sick if you play it for long enough.
After the annihilation of each wave, you have to dock with the mothership before the next wave appears.
Look out for the Tardis as you manoeuvre, and don't shoot the Doctor (he doesn't score anyway!).