It occurs to me that your question is to "represent each system the best." This is an unflattering exercise, but here goes....

Colecovision: single-screen blocky sprite maze, or janky scrolling, with resolutions only one step above VCS/Intellivision graphics.

Sega CD: low resolution "screen door" full motion video, with lots of loading time

3DO: higher resolution versions of Sega CD games, early 1990s "multimedia PC" ports, nice still shots but stiff controls

Dreamcast: SEGA arcade ports, with lots of pre-PS2 late 1990s PC ports shoveled in

Saturn: SEGA arcade ports, a few excellent scrolling shoot-em-ups, a bunch of Playstation and the occasional 3DO port

I think that playing the best games on each platform is a better way to go. Just about any non-current platform can be eviscerated by listing the traits of its lowest common denominator in software.