Even in the PC world, the most common resolution in for CGA, EGA, and VGA remained 320x200 for many years. With square pixels, this would be 16:10, but the usual case was that this resolution was displayed fullscreen on a 4:3 display, so individual pixels would have an aspect ratio of 5:6.

Most DOS-era games took this into account, so e.g. if the artist wanted to draw a circle 20 pixels tall, they'd make it 24 pixels wide. Textmode followed this pattern as well, so when rendered on a modern square-pixel display without aspect correction, will look vertically squashed compared to their original appearance.