I like the way this built up. The various elements were introduced softly so you could hear it coming but not so much that it was jarring. Every time it started to verge on repetitive, you added in something new. At 5:39, it might be interesting to try having each element fade out over 2-3 seconds, as right now it hits a high note in the pattern, then goes right into the soft hum. If Parallax paralleled itself (ha) by removing elements the same way it introduced them. Just a thought, and it could lead to the song being a good loop that you can lose yourself in, never knowing where the end is.