One of those megademos you just sit back and enjoy; no tedious scrolling text or terrible chip music here. The Grotesque Demo has a neat, if rather manic, sampled soundtrack. The visuals are flashing images, mostly one bit-plane and 3D drums and shapes.
The two tie in together making a terrific groovy little raver of a disk. OK, so you're not going to run it zillions of times like a top game, but it's great fun the first couple of occasions and is a good answer to those people who come round, take one look at your ST and ask what it can do.