Overall:
Since this is from brawl, maybe put "Super Smash Brothers Brawl Bros SSBB" in the tags?
The BG is not 4:3, so it looks stretched. Use
This one or
This one, or find another one that is 1024x768?
Hitsounds should stay consistent. I suggest a whistle on counts 2 and 4 owo
02:48:381 - I'm on a hunch that the BPM changes around here somewhere
End the diffs at the same time!
Hard:
00:12:342 (4) - The way this note comes after the slider is awkward for players, and doesn't look good. Have it follow the natural flow of the slider (aka going to the right.)
00:14:874 (4) - Move this elsewhere so it doesn't overlap with (3)
00:17:991 (3,4,5) - Keep consistant distance spacing so this doesn't look so cramped
00:19:939 (8) - Move this so it's not overlapping (6). It's slightly hidden and plays awkwardly
00:29:485 (11) - NC (It's hard since the way you mapped this, it doesn't directly follow the lyrics, so the place where I would have NCed is during this slider.)
00:40:589 (4) - This sounds and looks better as a longer sliders without as many repeats
00:46:433 (1) - I'm never a fan of two spinners in a row. Maybe make it a long slider, and at the second "ah", put a repeat
00:51:692 (7) - Make this a regular ) curve.
00:53:251 (8) - Doesn't fit with the song
01:08:251 (6) - If you're going to have this slider, either stack it under (4)'s end (which I wouldn't reccoment personally, but it fits with the style of the previous section), or move 5 below (4)'s end so 6 can just flow in there.
01:15:653 (9) - NC
01:28:121 (1,2,1,2,3,1,1,2,3,1,1,2,3,1,2) - Delete these notes. There's nothing wrong, but to go with the full musical phrase, it'd be better to just leave these as part of the break.
01:40:589 (6) - NC
01:52:277 (8) - Make this slider more interesting
02:51:498 (1) - Remove NC
Normal:
Biggest issue I have with this is that this seems way too similar to Hard.
00:29:679 (3,4,5) - Umbelievable amounts of confusing
00:33:576 (7,8,9,10) - ^. Also, NC on 7
00:53:056 (5) - Move back to the white tick
00:53:835 (6,7,8) - ^
01:03:965 (3,4,5) - Make it so these don't overlap
Easy:
Seems really easy and boring compared to normal. Which means make this slightly more interesting and tone down normal by a lot.
Also, just as a general thing, for most sliders with repeats, make them longer with less repeats
SV can afford to go up a bit.
Cool.