@ rendo
I hate online achievements like that.
Score 5 goals in an online game sure but 300 games? Maybe offline.
My firend has to get something like 50hrs online in fifa 09 or 10 to get an achievement worth 1gamerpoint (I don't play the game so have no idea which the achievement is) and at the moment his gamerscore is 27,999.
He's not happy.
He's also trying to get an achievement for having 10 players in a game but can never get them to stay til the end of the game. I've suggested he uses the boosting section on true achievements to get enough players who will stay.