: The PC does have a few Mac emulators, some good, some bad, but none of them
: can run Marathon at a decent framerate, if at all.
I can run all the marathons under basilisk II on my 600mhz athlon system (running win2k; basilisk II will run under win9x, but im not sure how well it plays marathon there) at very acceptable framerates, even with music and stuff turned on. i think it runs a bit slow though - not framerate slow, but the game is sorta in slow motion. not by much, but its noticable.
you'll also need a mac bios image and system to run it. you can get os 7.something off apples site for free, but you'll have to have an acutal mac to get the bios off of (basilisk comes with a tool and the instructions on how to use it to dump the rom onto a disk).
