Check 'em out!
These are NTSC artifacted images. ~200 + colors, captured off a real CoCo 3. Check the Kings Quest one... And the 130 color Sonic one at top!!
Unlike other CoCo 3 hi-color methods, this one requires only a composite display. No interrupts, or CPU time required. It's just a full on 160x200x256 bitmap, with some of the colors duplicates, resulting in a 200+ color display.
(Yes I geeked out on a CoCo 3 this weekend, but I've wanted to render some pictures on it for a long, long time. Got some help from Jason and Briza.)