For the actors themselves, the Reding brothers demanded people who were "absolutely, 100% believable on the big screen ... This is the reason why the actresses and actors in OI!WARNING are a good mixture of non-professionals and professionals": male leads Sascha Backhaus and Simon Goerts were non-professionals, whilst female lead Sandra Borgmann was an established actress when the project started. A problem was money, because the "Oi! Warning" production was very low budget. It took over five years to complete, because the Reding brothers frequently had to stop filming until they had earned enough money to continue.