According to the end of the video, it looks like you can have it interface as a mouse too. So you might be able to make so more fancy analog input.
And I think it also said it can interface as/with an arduino, so I imagine a lot more is possible if you are creative!
Also, obviously you can make your own DDR dance pad (not with water though... I would use metal plates, make more sense).
Or create some wacky musical instruments...
Too bad it only interfaces with keyboard it seems, thus lacking some serious analog input... Although I don't know if it CAN track analog input anyway.