Dang it, this is one of my favorite vocaloid songs...! I sincerely hope this would be ranked soon.
Suggestions are:
[General]
background image is too big; it took a lot of time to download the osu file. What about shrinking it using Paint or whatever?
I personally suggest to decrease the circle size considering the difficulty (insane).
[Mapping]
Generally, the combos don't really look consistent. Try changing them overall.
Also, many sliders have bad shapes. BATs don't really like those, you know... try fixing them, here's an useful tutorial:
http://osu.ppy.sh/forum/viewtopic.php?f=56&t=3719400:03:611 (2,3,4) - try using neater positions.
00:04:747 (2,3,4) - 4 is being practically and temporarily hidden by 2.
00:15:883 (1,2,3,4,5) - what about using a star pattern (
http://osu.ppy.sh/wiki/Star_Patterns) instead?
00:45:882 (1,2,3), 00:54:972 (1,2,3) - unnecessary new combos? There are lots more.
00:37:928 (2,3,4) - unnecessary jump? try changing spacing.
00:39:746 (3) - move it a tiny bit so it fits to other circles.
00:49:291 (1,2,3,4,5,6,1,2,3,4) - overmapping?
00:58:609 (1,2,3,4,5) - 3 is being hidden by 1.
01:03:836 (1,2,3,4) - unnecessary jump?
01:00:199 (1,2,3) - same as 58:609.
01:17:244 (7,8,9,10) - try relocating them so they are equal in distance.
01:39:061 (1,2,3,4) - try using different positions.
02:34:968 (2) - should this 2 really be far away from 1?
02:36:786 (1,2,3) - you can make them prettier by simply tweaking their positions.
03:07:012 (7) - that's an awkward location for that 7. what about moving it down a little bit at least?
That's all I can notice so far; good luck! The rhythm looks fine for me, and I'll assume that the lack of hitsounds is due to incompleteness.