The fact that the document targets multiple architectures is great, most ASM tutorials online target solely x86 and as such give a very partial view of how assembly is written and how CPUs work, and on top of that x86 ASM is really quite a mess.

I've skimmed the document and it seems rather thorough and doesn't shy away from all the nasty details (which is a good thing for an ASM tutorial), the only criticism I have so far is that the assembly listings are a bit hard to read, additional whitespace and basic syntax highlighting (at least to isolate the comments) would make it a bit easier on the eyes I think, for instance: https://svkt.org/~simias/up/20180717-151848_asm-listing.png