Rumble | Mini-Game Versus Minigame

As a writer and editor, producing blocks of text with correct grammar and usage is of the utmost importance to me, so it is not unusual that I check myself with the occasional dictionary reference or even peer review. More often, I find myself using the Videogame Style Guide for industry-specific terms that may not have officially found their way into common language as of yet. Usually I follow that to a T, but in this case, I had to contest.

The word minigame (or mini-game) has been used throughout the industry for quite some time now, but which is the proper way to write it? The Videogame Style Guide says that "mini-game" is correct. What does the internet say?

Minigame is in RED
Mini-game in BLUE

That seems pretty clear to me, and Wikipedia confirms the result. Minigame it is.