they do.. its something called a game engine. http://en.wikipedia.org/wiki/Game_engine you need the main os to tell the computer what you want it to do. the os in conjunction with software work together to achieve this. you need to do some reading.
This is what java was kind of supposed to do. Since most all internet browser's support it, game makers can now build games using java so they can be cross platform, letting them run on Macs, pc's, and portable devices like phones and such. Though, having a game on a cd that you could boot your computer to and just play it like that would be pretty cool too, but I think they would run into problems because of all the different types of hardware that people have in their pcs all over the world.
Yes. And PC games require api calls and such to Direct X, which mac lacks (unless you run Bootcamp, but that would be cheating ). But now i have a question: how does Blizzard manage to create games such as Diablo that are compatible with windows and macs? Precisely, what is the core principle that judges whether a pc game can be played on a mac and vice versa?
that is an interesting question. thing is i don't know much about macs to say what it exactly is. imo obviously pc will out-do the mac in the gaming industry so there is little incentive to create compatibility with mac. what is it something like 90% pc and the rest goes to mac/linux... they even had to create bootcamp to allow for pc platforms to run. poor mac.
They put in the ridiculous amount of hours to recode it specifically for MAC. Blizzard can get away with doing this because they are huge($$). Most companies don't bother(even if they have the $$) because they do not see the MAC market as being worth their effort. I would say most gamers do not buy MACs, but that is just speculation. I'm sure some angry MAC gamer will contradict me.