From my understanding, subdomains are “specific file cabinets” for your site. For your site, it sounds like you’re seperating out based on game of choice, which will allow you to get more specific backlinks if you chose to do so. Additionally, the user is at an advantage, as they “know” where to go to look for info.
Additionally, if you were targeting say the UK, USA, and Germany, you can set each subdomain to target such audience in Google Webmaster tools.
The only “disadvantage” i see is that google almost considers subdomains as seperate sites from your main website. Though, in knowing this, one can be certain to use that to their advantage as well as put meaningful content on each area of the domain.
Mike