There are several long mixes like that on the Bandcamp website.
Should those be added?
Sure they're video game related, but they remain single-tracks.

/feedback

I think we need to figure out just what this bandcamp scene is all about. Are these really considered as releases, or do amateur musicians just use it as a spot to showcase things that might be considered works in progress or demos. We could easily get swamped cataloging a lot of non-release-quality stuff.

Yeah, that seems to be a problem. I refrained from adding single-track releases because of that.
(Uploaded this one though, as it's a pretty long mix, so it "could" be considered a release on its own)

Could you listen to this, and figure out what games are on here? That would make the case for this entry much stronger.

So far, I've spotted some mega man 2 & castlevania covers. Will add them for the time being (even though there are loads more in it).

There's also segments of this mix that are "mashuped" with some (unknown to me) rappers lyrics.

There's definitely lot of music on Bandamp.

Bandcamp is a sort of Myspace, so can be considered to have a huge majority of fan/amateurs music.
Though & unlike Myspace, it's clearer and solely dedicated to music.
It's also providing a system to share/stream & sell directly music. The price is always choosed by the seller/owner.

So it's probably the best platform for cover bands / amateurs to distribute & sell their music in digital format.
But there's also a few known artists to be found there, like:
Howard Drossin, Jake "virt" Kaufman, Sam Hulick ...