I could be wrong, but I always thought Keen was written with VGA cards in mind and merely used EGA because of that dual-page mode..
By 1990, the EGA card was already 6 years old and got supersed by VGA just 3 years ago.
Anyway, I believe that memory issues *could* be among of the issues. 😐
A VGA card has the full amount of EGA memory. 64KiB is by far too little. This can't even handle 640x350 properly.
That amount of RAM i's nice for beefed-up CGA games with 16 colours, though. Especially if no real EGA monitor is used, anyway.
"The original IBM EGA card had 64 KB of onboard RAM and required a daughter-board to add an additional 64 KB (cards with 64 KB are limited to
four colors when 640×350 mode is used). All third-party cards came with 128 KB already installed and some even 256 KB, allowing multiple
graphics pages, multiple text-mode character sets, and large scrolling displays."
https://en.wikipedia.org/wiki/Enhanced_Graphics_Adapter
Also, timing is different, as well.
VGA runs EGA modes in 70Hz, whereas real EGA runs at 60Hz.
"Time, it seems, doesn't flow. For some it's fast, for some it's slow.
In what to one race is no time at all, another race can rise and fall..." - The Minstrel
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