Taiko mod by request.
[Inner Oni]
00:03:185 (9) - k? To follow the pitch of that guitar note.
00:08:038 - d here to make a ddk triplet? Makes this longer string of 1/2 a little more interesting and leads into the next roll nicely.
00:12:009 (63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79) - This pattern sounds really bad with the kat placement and the amount of finishers. Playing it is also a pain. try to follow the guitar more while still adding the finishers, but keep it simple for the sake of the player. (These finisher+triplet patterns are a pain if not done correctly.) Something like: D ddk D d ddk k D ddk D d ddkdk can work nicely. Keeps your finishers and sounds better to the music and is also a lot more readable. (D ddk D ddk d k D ddk D ddk d k works aswell, a little more difficult if that is what you are looking for. Or just do something along these guidelines.)
00:15:538 (88,89,90,91,92,93,94,95,96,97,98) - You should cut all this 1/4 out and focus on just the finisher pattern. The 1/4 doesn't really fit when the song is just doing these finishes.
00:25:067 (145,146,147,148) - Try k d K K D instead. Adding that first kat keeps the pattern going from the one before (k d d k d d k kind of structure) The way you have it feels like it skips a beat because you broke this pattern (don't forget to make the k you had before a d). And changing those 2 D's into K's for the pitch of the music.
00:35:303 (206,207) - switch these around, do it's k d not d k.
00:36:362 (214) - Make this a k. All these dons feel kind of empty.
00:47:126 (271,272,273) - Make this 2 notes instead of a triplet? Going from that pause into 1/4 felt awkward and breaks accuracy.
01:01:420 (365,366,367,368,369) - Make something out of this pattern? Just dons is boring, ddkkd or ddkdd work nice and keep the flow going.
01:33:891 (43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64) - Same things as before apply.
01:37:420 (68,69,70,71,72,73,74,75,76,77,78,79,80) - Same things as before apply.
[Oni]
Everything looks good here, really nice oni.
[Muzukashii]
I think your intro is a bit undermapped for a muzukashii. Fill it in a little more?
This seems suitable for muzukashii.
Everything else in this diff is really good too! I'm starting to love this spread. I do want to mention though you shouldn't be afraid to use some 1/4 in muzukashii diffs. Players do need to get used to 1/4 before they step into Oni level play, just don't overdo it!
[Futsuu]
Flawless!
Wait one thing actually. consider shortening those Spinners? Long spinners might take a newbie time to complete so they should be a little shorter. Kinda the exact opposite of what spinner are like for newbies in osu! xD
[Summary]
I really like this, the difficulty levels have a great curve to them and are not too far apart in terms of difficulty!
I think you should try and work with your finisher usage and consider how they tie into the pattern you are useing.
okbye.