The awkward situation where the banner says "play the full game", while the game actually only allows versus levels to be played is a result of miscommunication along the lines between development and marketing.
We are very sorry that this has happened, but I can assure you this was out of Croteam's control. In any case, we (Croteam) have decided that the only fair way to remedy this is by fixing the game to allow unlimited access to all game modes, including Single Player, Cooperative, Survival, Beast Hunt and all others.
Note that due to time zone differences we cannot do this immediately, but we will do our best efforts to get it fixed ASAP. It should be enabled correctly before Saturday, so everyone should get their free weekend.
We apologize for the inconvenience and hope that our customers understand that not everything is under our control nor can everything be done without ever making a mistake. However, we stay committed to giving the best service possible to them.