Sound was working, but transparency wasn’t, so in certain parts of certain games e.g. 600 AD in Chrono Trigger where there was a fog effect, it would be opaque, and you’d have to go into the emulator menu and switch that layer off to see what you were doing.
But hey, it ran at playable speeds on a Pentium 1 / 100Mhz so it wasn’t all bad.
Yeah, the SNES sound chip is notoriously difficult to emulate and even now it’s not perfect, especially with things like wind sounds. The water rushing sound in Zora’s Waterfall in Link to the Past sounds really harsh and distorted on emulation compared to original hardware.