The card example wracking Agony in the latest designer diaries has two penalties depending on the number of chaos stars rolled.
The first involves turning over a single wound card and making it a critical, or if you have no wound cards you take one.
The penalty for two stars is "as above" except that you turn over two wounds cards making them critical.
If taking the RAW (on the card) this means that you turn over two wound cards making them critical, but if you don't have any wounds you only take a single wound card (not two).
However, perhaps the idea behind the card is that if you roll two stars you get two criticals, if you don't have any wounds you take TWO wound cards.
Without any other info (perhaps some standard example/rules appear in the rulebooks) I'd be inclined to assume the second interpretation, even though with the RAW, you have to take the first interpretation.