I have Game collection in my DB:
var game = { players: [{username:\"user1\", status:\"played\"}, {username:\"user2\", status:\"accepted\"}] } <
If you only have one other status than "played" use the query:
db.games.find({ "players.status": { $ne:"accepted" } })
You can adjust the query to handle more status values, as long as they are all known at the time of the query.