Adapting game’s evaluation metrics to virtual reality serious games and its validation on 'Hellblade: Senu’s Sacrifice' (Preprint)

BACKGROUND The design of Virtual Reality Serious Games (VR-SG) is a subject still developing. One of its open developments is the definition of metrics to evaluate the fun and learning result. In this way, weaknesses and strengths in the design of serious games can be found for future works in this research field. OBJECTIVE This paper aims to create a metric that can be used to rate the gameplay of VR-SG. This metric’s novelty allows to evaluate the different fun and learning features and give them a quantitative rating. A study case shows the capability of implementing this evaluation to identify strengths and weaknesses of VR-SGs. METHODS The new VR-SG metric is developed on the basis of the Mechanics, Dynamics and Aesthetic (MDA) framework but including User Experience (UX) elements and adapting them to VR-SG. This metric includes 1) UX aspects: VR-headsets, training tutorials and interactive adaptions to avoid VR inconveniences; and 2) MDA aspects: exclusive VR audiovisual elements and its aesthetics interactions. RESULTS The selected indie serious game is Hellblade, developed to raise awareness about the difficulties of people suffering from psychosis with two versions: one for 2D-screens and the other for VR devices. The comparison of metric´s scores for both versions shows: 1) some VR dynamics increase the gameplay impact and therefore, the educational capacity; and 2) flaws in game design where the scores drop down. Some of these flaws are: reduced number of levels, missions and items, lack of a tutorial to enhance usability and lack of strategies and rewards in the long-term to increase motivation. CONCLUSIONS This metric allows to identify the elements of the gameplay and UX that are necessary to learn in VR experiences. The study case shows this research is useful to evaluate the educational utility of VR-SG. Further works will analyze VR applications to synthetize every game element influencing its intrinsic sensations. CLINICALTRIAL The trials have not been registered, as testing for this metric has not involved people with mental conditions or addressed other medical applications. Hellblade is a commercial video game that anyone can purchase and play. The trials have been carried out to obtain results on the gaming experience of different people in relation to the educational purpose of raising awareness of psychosis.