Agree completely. Some form of minimum requirements filtering is really needed. In my games I write “minimum year 20XX” but that sort of thing never pops up in searches (neither does “OpenGL 2.1” or something like that).
There’s a lot of tiny details, though, like games that have a minimum OpenGL version or enter software rendering mode, requirements that don’t correspond to any particular machine builds. Will there be a predefined list of allowed tags, or can people write in their own?