&gt; The result is encouraging: for instance, the 512C &quot;your emulator suck&quot; screen in Overdrive correctly works (at least in the PAL version IIRC). I think I hit a limit with the way timing was computed in the CPU cores I was using, and then dropped it for boredom. There were also a few regressions, visible in Overdrive itself (which is almost perfect on master, with the 512C screen being the big exception).<p>Overdrive is tough. It has some nasty race conditions in it and of course the 512C scene requires a reasonable approximation of the reduction in sprite capacity. I don&#x27;t have it working 100% myself (wanted to get some other timing related things tightened up before trying to chase down the cause of race that doesn&#x27;t happen on real hardware). I commend you on getting as far as you did.<p>The moose chase level of Mickey Mania is another good thing to check out as it also requires emulation of the sprite capacity reduction.