It's hard to put a tag on Cluster's output. The first album sounds like a bad trip if a bad trip would sound amazing. The second album has shorter tracks, flirting with song-structures and here and there some light in the darkness. Fast forward to Zuckerzeit, where the incomprehensible becomes comprehensible. Still weird as ever but now with actual melodies and 4/4 patterns. After that it became a lot of things, but in my humble opinion never so futuristic as the first two albums or so danceable as Zuckerzeit. So a real answer to the question 'How would you define the Cluster sound' is not exactly possible. Does this matter? Ofcourse not. People seem to have their favorite 'periods' from musicians or bands. Or favorite albums. Usually this has to do with a cringing sense of nostalgia, but when 'Cluster II' came out my father was still in his diapers. Well, not really, but you get my point. And yes, 'Cluster II' is my favorite. Especially 'Live in der Fabrik'. That track, ladies and gentlemen, is how space would sound if it had a soundtrack. If you are a fan of Donato Dozzy, Bee Mask or Valerio Tricoli, I highly recommend 'Cluster II'. You will admire it for its creativity and sheer futurism. Suck it up - indulge yourself. After that, listen to this album. It's even better.