This state of the art aims to look at factors that may influence feedback effectiveness in serious games. Feedback is a post-response intervention during the learning process that provides the learner with information about his actual state of learning, to improve his performance and/or knowledge in the light of an expected outcome. Feedback is an important component of serious games to stimulate and deliver an effective learning experience. It provides the learner with specific information about their skill- or knowledge-related performance, at a particular stage of a game. Feedback is a complex, multi-faceted component of serious games. Its effectiveness depends on balancing out its main properties: Content, timing and modality of delivery/presentation. Two factors play a decisive role here: The amount of information to be conveyed and the level of disruption the learner will have to endure. Simultaneously, this balancing act needs to be performed while taking into account the learning and the gaming contexts, the learning goals, the expected learning outcomes, and the target audience.