First, watch this and pay close attention:
Second, dealing with press can be a full time job. It will take lots of work, repeated direct contact and emails to dozens of people, and then just maybe someone will notice you. Game journalists don't really care about press releases unless you're somebody who already has their attention - and frankly, you don't want coverage from anyone who's picking up press releases.
What I would suggest: look up game journalists, see what they're writing about, and when you find one that could be genuinely interested in what you have to show, let them know about it (I know, it sounds simple stupid, but it works).
In your case, finding a metalhead seems like it would be ideal, and I think you can find a few around IGN/RPS/Kotaku if you look deep enough.
Next, find a way to present the idea to them under such a light that it sounds like a "story". Doesn't matter what the game is, it needs to be sold as a story that they can rally readers around. So start thinking: what funny things happened when you secured licensing to show portraits of actual people? Did they give you show tickets to convert rookies to the metal scene? Did any of them say anything to endorse you? etc.
This is great advice.