Emotion regulation is a topic that has considerable impact in our everyday lives, among others emotional biases that affect our decision making. A serious game that was built in order to be able to train emotion regulation is presented and evaluated here. The evaluation consisted of a usability testing and then an experiment that targeted the difficulty of the game. The results suggested adequate usability and a difficulty that requires the player to engage in managing their emotion in order to have a winning strategy. © 2013 Springer-Verlag.