- We strongly recomend that you play the newer IREM games in pure DOS. Why? Runs much better in pure dos. These games are extremely hard to emulate with decent speed. Why again? First of all the main cpu runs on 18 Mhz, they have 3 layers with VERY complex priority functionality. So in worst case we need to split them up in 7 different layers and some tiles must be redrawn twice (some pixels in one tile has a lower priority than other). Another reason is that they can show 1024 different colors at the same time on screen, and they change the palette VERY frequently, so its tough to handle. And as a last killer reason they are able to have 2048 sprites simultaneously on screen. Its also recomended that you use -f if your framerate is low... and it propably is ;-)