It's a huge, atonal mess to someone who doesn't play an instrument. Whatever they're doing might have some technical musical significance, the sole reason I haven't 1'd this, but Meshuggah sounds a hell of a lot better pushing the boundaries of metal.
awesome album. loads of syncopation. odd time signatures. may be some metric modulation, not sure, but the tempo definitely changes a couple times during songs. vocals are perfectly attuned to the other instruments. everything is tight as. harmony is mostly atonal, but you get the odd bit of something which may resemble something tuneful. doesn't last very long. More technical than ion dissonance, more experimental as well, but lacks the same level of passion.