Navagon: GOG seem to only update it once a week or so.

DrIstvaan: I don't think it's that consistent; once, I saw it updated several times a week. Also, it's been more than a week since the Another World+Sanitarium promo.
Anyway, they probably just forgot/didn't bother to update it recently.

Navagon: I doubt it's so backward as to be manually updated. But it's not very consistent, so who knows?

lukaszthegreat: there hasn't been change in a while... any change. so either for some reason everyone buys all the games every week in the same proportion and quantity or it is stuck because it is manually updated...