> Many (maybe most?) video games seem to have been written in a VM, at least before Doom / high performance 3d graphics.
This was not terribly common, for the obvious performance reasons. Another World ran at around 10-20FPS on most of the systems it was released for, which is fine for a methodical game like that (and for adventure games like Monkey Island, etc.) but doesn't work for fast action games.
And of course VM games were basically impossible for the entire 8-bit era, with the exception of things like Zork (and the rest of Infocom's Z-Machine games) whose performance needs were so small that the gigantic overhead of an 8-bit VM was hardly noticeable.
Even into the 16-bit era, the majority of multi-platform games were fully rewritten ports.
This was not terribly common, for the obvious performance reasons. Another World ran at around 10-20FPS on most of the systems it was released for, which is fine for a methodical game like that (and for adventure games like Monkey Island, etc.) but doesn't work for fast action games.
And of course VM games were basically impossible for the entire 8-bit era, with the exception of things like Zork (and the rest of Infocom's Z-Machine games) whose performance needs were so small that the gigantic overhead of an 8-bit VM was hardly noticeable.
Even into the 16-bit era, the majority of multi-platform games were fully rewritten ports.