A cool tune made by Richard David James/AFX/Aphex Twin for his alias "The Tuss".
The GX1 is a very rare Japanese synth which was released in 1975. Only about 100 or so of them were ever manufactured. (or some other small number i forget, sorry)
Something I like about the synths in this EP is how they sometimes sound like they're being recorded on a mic in a room, it's pretty neat.