Ambitious project you have here, considering there's all of about 0 repeated frames in this album

So congrats on completing two of these, it's more than I could do. This album is a favorite of mine, so I'm happy to see someone else working on it.
Overall the notes in both songs are pretty good - there's a ton of slightly off notes and timings, but it'd be nearly impossible to get them all right, especially in a tracker - I'll attach my unfinished 21stCSM so you can compare the notes, see if you think you missed any. Probably the biggest criticism I have is for the instrumentation - A lot of them feel kind of "flat". Here's my feedback:
21st:
- The bass could have some punch (12 0 arp) or be a more interesting wave than tri + saw. Maybe some decay and S0X note cuts?
- The DPCM tom sounds out of place
- Voice sounds cool but kind of soft
- The guitar has slightly different/more full chords in the intro I think
- I think frames 09-0C are off with the guitar/sax - they switch octaves and notes at some point
- When only one lead is present, some echo might sound cool (like the guitar frames 10-15)
- I stopped my cover around frame 17 - so great attempt at getting this manic section correct, it turned out good
- Stuff needs more vibrato in general
- Can't blame you for not doing the ending
- Overall the piece doesn't have the insane dynamic range of the original, but it's to be expected with 4bit volume
- Again, instruments are just kinda simple and lackluster, especially for N163.
Wind:
- The flute really needs some attack and vibrato - it sounds unnatural otherwise. (Maybe use a namco channel?)
- Vocals could use some release or S00 between notes
- Flute echo on frames like 11-12 might sound nice
- Arp (frames 04-06) doesn't fit imo. Maybe you wanted the gritty arp sounds to come through here?
- This piece gets more of the volume dynamics right
Sorry for the wall of text, but hopefully it helps. I wish you good luck with the rest of this. Moonchild is gonna be tough, I imagine.
Also, your album art isn't showing for me, but I'm guessing it looks a bit like this (album art converted to an NES .rom hehe):

And btw, are you on a mission to cover all of /mu/core or something? I'm expecting Death Grips covers at this rate :^)