00:52:964 → 01:11:787 - The kiai could be slightly reworked to better represent the vocals, which I believe is what you're mainly trying to represent. Here are some suggestions of what to do.
The musical representation in Kantan currently is not very good.
The density is quite low, and some sections with different rhythms and intensities have been represented in very similar ways, resulting in no contrast between sections, for example at 00:01:199 → 00:09:434 and 00:10:611 → 00:20:023, in which the second section sounds a bit "faster" due to the addition of the kick sound every 1 beat.
Another problem is the large repetition of patterns at 00:18:846 → 00:38:846, which are several 2/1 triplets in sequence, leaving something to be desired in terms of variation and representation of different rhythms.
Although Kantan is a diff for beginners, you can still make more use of 1/1 patterns for a better representation of important rhythms that you want to emphasize, as you did in 01:09:434 (79,80,81), representing the vocals with a 1/1 triplet.
I'm going to give you some general suggestions for this; if you have any doubts, please let me know and I'll go into more detail.
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For the section between 00:10:611 → 00:20:023 you could do a small sequence of 2/1 triplets. As the intensity isn't much higher than the previous one but still has a different rhythm, this would give a good contrast between the two sections, representing the change in rhythm through the slight increase in notes.
You could add notes at 00:11:199 - 00:13:552 - 00:15:905 - 00:18:258 - (00:19:140 a 1/1 triplet here would fit in very well with the drums :)
You can also vary the colors of these triplets based on the different tones of the vocals / instrumental, something like:
Something similar could be applied to 00:21:199 → 00:40:023 section, adding more notes, but with more 1/1 triplets due to the increase in the intensity of the song. In this section, a lot of new instruments and sounds start to play, basing new patterns on them can add a lot of rhythmic variety to your map too! Let me give you some examples:
You could add notes at the following points: 00:22:081 - 00:22:964 - 00:23:846 - 00:26:787 - 00:27:670 - 00:27:964. Add these notes and notice the following, they're all focused on emphasizing the vocals + drums, they're the two sounds that stand out most in this section apart from the guitar. Placing notes where the tone of the main sounds is most intense is a great way to make the map sound good even at low diffs and with limitations. Just so you can see how it could look:
And finally, I want to mention kiai. Most of the time, the kiai ends up being the most intense part of the song, and in taiko, the tendency for most of the maps is the greater the intensity, the greater the density, it's not a rule, but it applies well here. I saw that you applied this principle to the kiai, it's denser than the rest of the map, but it's still not very dense and doesn't have such a good musical representation actually.
My recommendation is that you increase the density of the kiai a bit more by following the suggestions above, creating more occasional 1/1 patterns and trying to represent the most important and prominent sounds.
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Sorry for the sooooo long post, but I thought it was better than making several posts and getting disorganized D:
I'll check the diff again after the changes, and if necessary, I'll make separate posts addressing each remaining point :)
I did a general buff on kantan. I made it have more musical representation and more dense. Though I'm not sure with the breaks so please do assist me. Thank you for the tips!