I'm making quick progress. The road layer is now implemented. I've also implemented shadow support on the sprites, you can see these under the trees in the screenshots below. I *think* the graphics hardware is pretty much complete now.
I've started implementing the controls. The basic digital controls are done and I'll investigate the analogue controls next.
I will then double check the timings and interrupt handling of the driver as there are some quirks at times.
There's some other things to be done - some of the code could be optimised and refactored in a slightly better way. Once done, it should be really easy to add further System16 games to Jemu. I've been using finalburn as a reference - the source is much easier to read than mame :)
Regarding JSnes, just to clarify this isn't abandoned as such - merely halted for now.