Considering they had to write custom tools for pretty much everything, including a visual language and editor to design all art assets almost two decades before

Considering they had to write custom tools for pretty much everything, including a visual language and editor to design all art assets almost two decades before that became a thing in AAA games and create custom compression schemes down even -IIRC- custom floating point representation that would compress better, i'd say that .kkrieger was the one that took more effort and skill. (though a lot of that work was largely based on their initial work for .the .product). 8088MPH is certainly very cool, but a large reason is that nobody had bothered with the original IBM PC much before.