Super easy, just grab Vice.
I tried running the demo with it, but it just says, "? UNDEF'D STATEMENT /n ERROR /n READY"
Tutorials said I could drop the file (currently using the demo one) into the emulator window and it would run it, but that's not happening. Suggestions?
EDIT: I was using the wrong .exe of many. Now though I've mapped my keyboard to the joysticks, I can't get past the "press fire to play" screen...