Right, I just tried out pr2a.
The only major bug I noticed is that the port is not respecting the callback rate of the individual engines, and is assuming 60Hz. This means that AY, SNDH, and in the upcoming b4 core, YM will not play correctly. See engine_get_callback_rate(). I was able to crash the build reliably by trying to open a new file when an AY was playing, but I guess that's memory corruption due to the above.
I like the Jump function - I'll probably implement that one in the Mac version.
Looking forward to seeing how this develops further
Richard