1. Loopable tracks. Plenty of game songs out there take one on an emotional journey. But some just aren't "game ready" and fit for certain games.

2. Number of tracks, since some games require shorter music tracks. For example, if a level is 2 minutes long, it may be a waste to use an 8 minute music track.

3. I'd rather pay for a higher quality.

4. Yes. For sure.

5. There are a lot of places to look. Itch.io is just one of them.

1. Tracks must loop seamlessly.
2. The number of minutes is more important - I might only use one or two tracks out of an album.
3. I'd pay for a track I really liked.
4. No.
5. Recently, I've come to itch.io first, because I've found the music I like here.

Other information:

The track should not be repetitive. Someone is going to play my game for several hours (hopefully), the track must be varied enough and long enough that they're not switching off the music after 30 seconds. I tend to take two or three tracks and blend them because I seldom find this in albums.

My personal preference is for happy, melodic tracks and the track is more important to me than the person writing the track (i.e. I will buy / download from anyone who has the type of track I like.)

Working composer here. That was a fantastic idea to create this topic!

From my experience past experience working with devs they seem to prefer / need both short and long loops since they're more flexible. It seems that more complex songs (that will tell a more specific emotional journey) are usually where our custom services will better solve the problem for the devs.

However, let me tell you a different experience regarding non-loopable tracks.  

I've just composed a boss theme on my YouTube channel which is not really a loop (I think it's a "hybrid loop") and it's very chaotic, with no leitmotif and a lot of melodic, harmonic and rhythmic variation throughout the song, and... it's being one of my most visualized and liked song so far - which disproves a lot of traditional ideas as to how a boss theme song "should be", since some devs seem to be looking exactly for that.

So, I think that it's important for us composers to ask our fellow devs what they want but we should also offer our own new musical discoveries to them because that would exercise and develop our creative powers in our field and also offer new / novel musical perspectives that could potentially make the devs's games stand out even more, giving them an extra edge in the fierce competition of game production.

Video game music has evolved and became a lot complex on the technological front with dynamic, non-linear music being implemented through middleware, but music is still evolving in itself in the old fashioned way - through different ways of creating the same ol' loops. 

That's being done through new sound design thought processes, intellectual interpretations of melody, harmony, rhythm, space/time interpretation and understanding in the context of sound, and also through the interchange of instrumental technique studies (expression, articulation, dynamics, etc), and their effects on music composition. 

We as a composers can work on both fronts and offer music products and services for devs that don't want to meddle with too much technological complexities regarding music (samey ol' loops), but with something different in said loops, and also the opposite offering them products with music stems and complex separated instrumental layering (although they seem to be a minority in my experience).

So, my question for the devs would be:

What would be the function of the required loops? In simpler words, what do you need the loops for? 

Knowing what they need we could offer potential new solutions. For instance, instead of stacking 3 different loops so that a prolonged level is not boring and irritating, why not offer a music pack with "hybrid loops" of longer durations, functioning both as more nuanced emotional storytelling but also behaving in a way that's seamless? Maybe that will sound like a crappy and useless idea, but maybe some devs will find that intriguing and potentially useful. 

My 2 cents.