All the difficulties seem fine...But I'm on a little conflict with Insane. I'm not sure whether it's rankable with the in-combo jumps at what they currently are. Sure, they're fine, but eventually they might become a handful, such as 00:20:11 (2,3,4) - I'm uncomfortable with. I would recommend new combo-ing some of the jumps, but I'm not sure if it'll ruin any nice design.
However, I will pick on some other things. ^^
Please add a hitcircleoverlay.png. Or you can be a jerk and force the default skin.
And comboburst-2...How the heck did you make it so Photoshop and Paint can't the read the file? O.o If you supply me the original render, I'll make a better version of it. Just call me on #italian.