puzzles i was able to successfully solve: 000, 003, 005, and kind of 006 (i followed instructions.txt no problem but had to check the spoilers to figure out what in the world it meant by "the codes will fall in columns." i thought this meant something was supposed to vertically line up in the file...)
now i'm on 007 and i'm considering looking at the spoilers for this one too but i might just call it here.
if i had sorta thought more about it i may have been able to solve 001 and 002 but i just could not think of anything to try when looking at them.
and, for context, my brain was already kinda fried before i started playing. so maybe if i were more fresh i would have solved more.
i think 004 kinda tricked me. i thought that the "balance the budget" line meant i should try to group up the dollar numbers into two groups that, when group one is subtracted from group two, gives zero. this seemed like the right approach, as it's completely doable to split the numbers up like this. after adding them up, i them summed up the rows in the ID numbers column for both groups, and took their difference, and got a 4 digit code--and 4 digit codes had seemed very common up to that point in the puzzle.
but apparently the actual solution using the CSV file was much more convoluted than i had thought of. i don't think i would have ever thought to try removing the zeroes and then summing the digits in groups of 6... just doesn't seem like the kind of thing that would ever cross my mind.
not sure how useful any of that information is, but hopefully it at least provides some indication to you of what the puzzle's difficulty levels are, for whatever that's worth.
i really enjoyed the kinda jargon-filled writing and all the robot (i think that's what the characters are?) worldbuilding stuff. things like sticking wires in places, and transferring memory back and forth, and what not... it's good silly nerd stuff.
i did find some of the writing kind of difficult to understand (although, again, this may be due to my brain being fried). for example, when i first read chapter 2, i kinda thought nepenthe and aleph were siblings due to the lines about that. i think part of the reason for this is that, like, this is a sarcastic line from both of them, but i think sarcasm does not come through as well when reading a long text (that is formatted partially like a technical report) in notepad. everything feels dry and literal, at least a little bit.
of the puzzles i could solve i definitely enjoyed them a lot. my problem with these kinds of puzzles is always, like, i want to try the other ones, but i can't do that without going through the spoilers. but then of course once i do that there's really no way to come back to the other puzzle and try it again later.
i think having more hints would be at least worthy of consideration. e.g. puzzle 004 might have gone a lot differently for me if i knew i was looking for text. i think one thing to consider would be providing a little command line app that lets you quickly test different passwords for each puzzle, and this app could also provide hints (e.g. after you miss a puzzle like 5 times with a numerical answer it could say "not a number"). i think the ability to see where you're going wrong is what makes traditional puzzle games so much easier to make progress on than these kinds of puzzles where if you're wrong, you have absolutely no idea if you're even on the right track.
although, such a thing would detract from the beauty of a game that is completely cross-platform just by virtue of being nothing but text files and zip files. which i do think is really cool. so maybe just a longer spoilers.txt with more incremental hints would work better.
i loved the "Qt mark" joke.