i think the most appropiate for that could be mount a Forum like PHPBB for people publish their own "threads" and people at same time can post their comments or feedback
since the Forums can be "configured" for some "categories" you can config it for various types of Genres of games, off topic general discussion etc etc
also another "way" could be mount a EXE client app that "deal" with a mysql server online for make like your own "app" (client) for manage multiple things, not only the feedback and game publishing board, for example you can integrate in the app a component for paypal payments or for example in the part of "deadlines dates" (this could be entered when a group post a game project) make in another TAB a calendar style dashboard with that dates and name of projects for the users can view in wide range a lot of projects with the estimated date of finnish (i said estimated cos in software development you never know really when you going to end) but in a EXE app the possibilities of make your own "cook" of thing is unlimited overall if you using proffesional dev tools like Rad Studio C++ Builder