>>16312698
It really depends.
Properly made and especially instrumental one can not really work as a proper metal song but definitely will work as a soundtrack. Or you hire someone like Keiichi Okabe that somehow manages to make soundtracks working on loop while having vocals and being quite upbeat.
For metal there have been a lot of metal inspired stuff but to my knowledge there aren't any proper metal songs there. With exception being maybe Brutal Legend, never got to finish it.
Which is not really bad thing. Sound design in Quake or Devil Daggers is pretty fucking good, it just is not really metal. Especially DD with its lack of soundtrack and just enemy sounds being creepy as fuck during gameplay.
So basically it can be done on the loop, it just haven't been done amazingly on the loop, at least to my knowledge.