General
WTF is with the Super Sonic storyboarded on the first frame? Kill it.
Offset may be closer to 5246ms. Unsure.
Easy
Not gonna really mod this because easier difficulties bore me. xD
However, it seems your Overall Difficulty is a bit too high, after a quick play through the first part.
Hard
Well mapped.
00:15:40 (3,1) - It would look nicer if these two sliders were symmetrical. That is, make each half the same size.
00:56:16 (2) - New combo.
01:01:91 (1) - Don't have this touch the slider.
01:13:12 (2) - Replace over the end of 01:13:58 (3).
01:17:97 (1,2) - Switch new combos? Maybe.
01:24:94 (1) - Move so the end is over 01:25:85 (3,5).
01:33:73 (5,6) - New combo on one of these.
02:02:52 (7) - This annoyed me. It's over the repeat so I didn't know to repeat. I guess it's fine as-is but makes the map harder to read, thus is difficult to FC on the first try (at least for me).
02:03:88 (1) - End at 02:05:24 (1/2 back).
02:08:58 (9) - New combo?
02:30:70 (1) - No. Sadly without this you'll have a superlong break. You can fit something other than a spinner in there, can't you?
03:04:94 (6) - New combo?
03:09:79 (1) - Clap?
03:15:85 (1,2,3,4,5,6,7,8,9,10,11,12,13) - Combo is pretty long.
03:19:49 (13) - Same situation as with 02:02:52 (7).
ztrot's Reason
Not difficult enough to be worth 8 million points IMO.
Wasn't as fun as Hard. It may be because the Overall Difficulty is too high. Maybe tone it down. That should lower the highest score too. The lack of hitsounds may have something to do with it to.
01:06:76 (7) - Replace under 01:06:30 (6).
01:09:18 (6) - Replace under 01:08:73 (5).
01:32:52 (6) - Closer to (5).
01:51:91 (4) - New combo?
02:13:12 (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20) - Long combo is long.
01:41:00 (4) - Move end down to align with 01:42:06 (5,6).
03:05:85 (4,5,6) - Spacing between.
03:22:52 (7) - Replace under 03:22:06 (6).
03:24:94 (7) - Replace under 03:24:49 (6).
03:30:39 (9,1) - Swap new combos.
03:39:79 (8) - Move under (6).
03:41:91 (7) - Replace under 03:41:46 (6).
03:44:33 (6) - Replace under 03:43:88 (5).