Think of it from the point of view of the person tasked with finding the right composer for a game (on a big enough project, that's the music director.) They are short on time, and have to listen to dozens of reels. Are they going to spend an hour, or even fifteen minutes, on each of the initial reels? No. Assuming that they don't already know who they want to use, they're going to graze for things that fit what they're looking for.
Your best bet is to choose about five styles, and have a reel with a 8-12 second highlight from each of those styles. This ends up being about a minute. Fade each highlight in over a second, out over a second, and keep a second of silence between each. Then, if that reel catches the fancy of the listener, you can have a link for more information, that can have deeper, fuller tracks. However, again, if the music director is mostly interested in your orchestral score with a naval theme, having to sit through a couple of trap epics and deep house boomers to get to that, is not a good use of time, so one link per style for the follow-up is still better.
Another tip is to make the background images bland, but pretty, for each style. A slowly panning shot of a softly lit well-engraved orchestral score. A cut of slowly billowing clouds. Lightning strikes over an African horizon. That kind of thing – don't attempt to “set the scene” too much to force your trance anthem into a cyberpunk sci-fi horror aesthetic, because that will bias everyone who is looking to make some other game.