Well there are some things to improve:
1. All tracks have to loop seamlessly (check out the Title theme in the pack)
2. Current track starts off with some really cool idea (from 0:10 to 0:18) but then it just stops,
If he can make that piece into a whole track - I think it would work great.
3. So the current track should start at 0:20
4. As you've suggested the volume of tracks should be more or less on the same level throughout the whole length.
5. All tracks should come in pairs - explore, battle. Like in FTL.
Basically Battle is the same as Explore but has some badass beats added to it(or something like this).
6. Also the tracks should be a bit longer.
If your friend can do these changes, then it would be just great.