'K, I mapped the original version of this 3 years ago, so I might as well mod this:
General:
Tick rate 2 every difficulty would probably work the best here. Also, I don't like this mp3 quality. You can steal the one I used if you want, since it took me lots of help to get a good mp3 and I doubt it's much easier now.
Insane:
00:03:413 (1) - This note alone lacks any emphasis so this isn't very intuitive. It'll work much better if you start mapping from 00:02:995, because then it will feel intuitive.
...Actually, looking at this this difficulty is way too overmapped to work well as a standard osu! map. In particular, the beginning of the song should be a bit relaxing because the song is relaxing and toned down there. Instead there are short streams everywhere. This song in general has very few 1/4s in it and, as such, is probably best off without an Insane. Why? Because there is nowhere to insert a stream. As seen here, you can't make the map difficult without shoving in streams where they just don't fit the music.
However, do not delete this difficulty. Instead, convert it to a Taiko difficulty. It would work perfectly as a Taiko Oni, so just change it into a Taiko map and that way all your hard work won't go to waste.
Hard:
00:03:406 (1) - As I was saying with the Insane... *ahem* Start mapping from 00:02:995 because that's where this little riff starts. It'll feel more intuitive.
00:05:889 (6,7,8) - The (7) feels forced and contrived; there is nothing there in the music. Try starting a slider here instead; it should continue the flow without feeling forced. Also, streams like this are frowned upon in a Hard; save streams for Insane, but again, an Insane just doesn't fit this song.
00:10:027 (3) - You mapped to the guitar here, yet don't finish it with the very important downbeat, so it feels weird and unintuitive. Turn (3) into a hit circle and add either a hit circle or slider 1/2 after for better flow.
00:19:131 (6,7,8) - As said earlier, streams both don't fit the difficulty and just feel forced in this song. It's just not a streamy song.
00:24:510 (5,6,7) - ^I'll stop pointing out the streams now, but again, they just don't fit.
00:26:581 - Okay, now here is where you can put a stream if you want. It's very audible in the music and as such wouldn't feel forced. And, if you stacked it, it would be single-clickable and fit well in a Hard.
00:29:682 (2) - Why the slider? There should be a hit circle for each syllable in "Po-ke-mon" due to the amount of emphasis it has.
00:58:648 (1,2,3) - I would use a different pattern here. Try to make the location of (3) be significant. Ending in the center is probably the best bet here.
Just a few flow issues, and again, those streams both feel forced and really are out of place on a Hard. They make the map an Insane, not a Hard.
Normal:
00:03:413 (1) - Again, weird place to start. I would just delete this on this difficulty, though, and just start with the "I wanna be..."
00:23:275 (1) - Same as on Hard; you're skipping over the downbeat (long white tick) here, which is the most emphasized part here. You *need* to have something on that long white tick, whether it's a hit circle, slider end, or starting a slider there.
00:24:719 (X) - It just doesn't flow well without something here; having something on this beat here would feel more intuitive.
00:30:103 (1) - A clap? Dude, there's lots of emphasis here in the music; you're starting the chorus. I would use a finish instead; it would feel better.
00:57:413 (5) - While linear sliders were cool in 2008, they are unfortunately considered outdated in 2011. I would just make this a regular curved slider.
Eh, this entire map feels similar to how we did it back in 2008. Not sure if that's what you're going for, though. If you want it to be closer to a 2011 Normal, then overall you need to map more to the beat and less to the vocals/instruments.
Easy:
00:03:822 (1) - This feels awkward and weird because it's not on a beat, and you're not mapping fully to the vocals, either. I would put it on a beat and work from there.
00:23:891 (1,2,3) - A 1/2 stream... in an Easy? Wait, what?
Wait, actually, as it is, this entire difficulty is a Normal. It's definitely not an Easy due to all of the red ticks. Easy difficulties nowadays are mapped to the beat and almost nothing but the beat. PM me over the forums about whether or not you want this modded as an Easy or a Normal, because what I'll point out depends on what you want this difficulty to be. Don't worry; if you rename this to a Normal, you still won't need an Easy because it's under 3 stars. But in order for me to mod this properly, I need to know what you want it to be.