Hamster is an enigma. There is stuff that points to MAME code being borrowed - City Connection is missing a sound effect that wasn't working due to a single line of code commented out when the driver was originally written, that was uncommented when I asked. But there are also games with some better sound emulation - City Connection doesn't have the high-end FM distortion on the Germany level's music that you heard in MAME, and Gradius supposedly has more accurate and less glitchy sound emulation as well. The world may never know...