> The PC speaker sound effects are bad enough (which is to say "as good as they can be, but still bad") and sound "cheap"

They are lifted as is from Shadow Knights.

> which is to say "as good as they can be, but still bad"

They could be done better or even way better, it's just that wasn't an important target in any way. Especially considering the performance target of 486DX+ whicih wasn't not a cheap machine in any way in 1993.

https://www.mobygames.com/game/1952/shadow-knights/