Yeah, those old games needed a bit technical wizardry, sometimes. Games with memory requirements of 580k of conventional memory or under were easy to get running. Play games that required more and you usually ran into difficulties because you also had to load mouse driver, sound card driver and later, cd-rom driver into memory. And of course you only had 640k to play with. (Thanks, Bill "640k will be enough" Gates)
I remember being really proud of my final DOS config that was getting I think 615K or so by then end.