Graphics
SCI0 games were mostly made for the 16 color EGA graphics adapter.
SCI1 games were released as two versions: 16 color EGA and 256 color VGA versions. The 16 color versions are much more "ugly" and also smaller in size, compared to their 256 color counterparts. This was done for people with CGA/EGA/TANDY videocards and a low-memory setup.
SCI11 ended this tradition by adding an EGA 320x200 graphics driver that dithered the pictures dynamically from their 256-color source.
SCI2 games supported high-resolution 640x480 SVGA graphics.
Read more about this topic: SCI Games