Keith here, the author of the website! Thanks for posting about my little hobby here, it's actually the second time it's been mentioned over the years,
The site and tutorials started from the multi-platform build scripts I put together to make the original ChibiAkumas V1.666, It felt others could benefit from them, so I made some tutorials and put them on line
The tutorials were far more popular than the game, so I was motivated to start learning more assembly languages, making more build scripts and tutorials... well it got a bit out of hand!!!
You can see all the CPU's and systems I've covered here: https://www.assemblytutorial.com/
Your work documenting assembly language across platforms is a treasure of the internet and much appreciated thank you fir educating so many.