Here are all of the changes I would make:
I have a funny feeling that one of the maps treats its video differently to other difficulties. If this is the case, choose a single video/storyboard to use in every single map, avoid any differences.
Easy and Normal don't have any problems, though in order to separate Normal's difficulty from Easy a bit, increase the Circle Size setting by 1 and add circles at 00:33:056; 00:33:525; 00:33:642 and 00:33:760.
MH's Hard I feel is the most troubling difficulty. Notes are spaced too far apart, and time-wise, it isn't much different from Normal. Add some 1/4 step circles in some places, and instead of relying on "OH YEAH MR KRABS" for where you should place circles and sliders, listen to the bass in the background. It has a little variation to it, playing off-beat throughout the song while the voice is on beat.
I am not experienced enough to mod Insane.
That's everything, can't wait to see this map updated.