We've just received a copy of the Classification Board's report for State of Decay, which confirms that the game was refused classification as a result of the game rewarding players for using illicit drugs in explicit ways.
The report reads...
The game contains the option of self-administering a variety of “medications” throughout gameplay which act to restore a player’s health or boost their stamina. These “medications” include both legal and illicit substances such as methadone, morphine, amphetamines, stimulants, acetaminophen, ibuprofen, codeine, aspirin, “trucker pills”, painkillers and tussin. Of these, methadone, morphine, and amphetamines are proscribed drugs and the term “stimulant” is commonly used to refer to a class of drugs of which several are proscribed. Players obtain drugs by scavenging for them in the environment or by manufacturing them in a “Medical Lab”. When players find drugs in the environment the name of the drug appears onscreen and the drug is also represented by a visual icon such as a pill bottle or syringe. Within the “Medical Lab” players are prompted to make substances such as “Potent Stims”, “Mild Stims” and “Painkillers”. The laboratory includes a “research library” and “chemical dictionary”. When administering drugs, the player is briefly depicted moving a pill bottle toward their mouth. The sound of pills rattling in the bottle accompanies the depiction. The name of the drug appears onscreen along with its representative icon. Consumption of the drug instantly increases a player’s in-game abilities allowing them to progress through gameplay more easily. The Applicant has stated that a “player can choose not to make any drugs or scavenge for them, but it would be very difficult to complete the game without some form of medication”. In the Board’s opinion, the game enables the player's character to self-administer proscribed drugs which aid in gameplay progression. This game therefore contains drug use related to incentives or rewards and should be Refused Classification.
Other games have shown illicit drugs being used before, but it appears that the issue is that the game would "difficult to complete" without using them. The problem is the use of drugs actively aids game progression.