RPG Maker

I feel like a lot of people probably know about RPG maker already, but if not it's available on steam and allows you to make your own RPG games, it's pretty basic as far as what you can actually create, but it's something i have recommended to past students of mine who have shown an interest in composing for video games. The reason i say this is because, even if you don't intend to be involved in making the games, you can still throw together something simple to put a soundtrack on top of in order to demonstrate your work in an actual game setting. You don't have to release the games on steam or anything, you could just screen record yourself playing it, or just put it up for free on your website so people can experience your music whilst gaming, instead of just your music with picture. I'm sure there are other similar pieces of software out there for you to be able to do different styles of games.