For example, another person and myself logged a bug on the Rygar core in in GitHub in February, and I'm pretty sure the Donkey Kong weird sound issue has been present since it's release. (compare to videos orf original PCB, 60-1 or MAME sounds).
I gather the intention of all cores is to eventually be identical to original PCB's (as closely as possible). It's just a shame to get them so far along then they get abandoned at 'good enough'. Then again I appreciate all the new cores. What a wonderful problem to have!
![Very Happy :D](./images/smilies/icon_e_biggrin.gif)