EngineDragonfire is the only commercial game sold by Radio Shack (and one of very few commercial program for the TRS-80 Coco period) that combined two different hi-res screen modes at once to squeeze more colors out of the screen. Using intricately timed programming during the drawing of each horizontal scanline, Frank changed the screen mode up 5 times per scanline to get the extra colors (8 real colors at once) instead of the usual 4 that other games used. Considering that there are 11,520 scanlines per second (60 Hz refresh), and the CPU only had 895,000 cycles per second, it is quite an amaziing feat. This broke a bit on the Coco 3, as the time was slightly different, and a patch was required to fix it.
Contributed by L. Curtis Boyle (734) on Mar 06, 2007. [revised by : joyvalley (148074) and Patrick Bregger (98904)]. -- edit trivia