From what I've seen, these are very open to interpretation. I think that It could be taken in as literal of a sense as you wanted: your game could be about an old gold miner, a character trying to recover something important that was lost to them, or even the "old (but) gold" saying, as long as your game sticks to its theme it should be fine. If the theme was very specific in its interpretation, such as "your game needs to somehow incorporate the concepts of age and wealth", it would have been written that way.