Kessel Run - a cooperative multiplayer SSVEP BCI game Inˆ es Cruz 1 , Carlos Moreira 1 , Mannes Poel 2 , Hugo Ferreira 1 , and Anton Nijholt 2 1 Institute of Biophysics and Biomedical Engineering, Lisbon, Portugal ines.cruz@campus.ul.pt 2 Human-Media Interaction, University of Twente, Enschede, The Netherlands m.poel@utwente.nl Abstract. Digital game research has been rapidly growing with studies dedicated to game experience and adopting new technologies. Alongside, research in Brain-Computer Interfaces (BCI) is growing in game appli- cations. Besides technical shortcomings, BCI research in gaming can also be lacking due to challenges such as poorly designed games that do not provide a fun experience to its players. In this paper we present a novel multiplayer Steady-State Visually Evoked Potential (SSVEP) game - Kessel Run - with BCI-focused co- operative mechanics, drawing attention to the impact of game design in the user experience. Twelve participants played Kessel Run using a 2-electrode cap and rated their experience in a questionnaire. The SSVEP performance was lower than expected, with an average classification accuracy of 55% and max- imum of 79% at a 33% chance level. Despite low performances, players still reported a state of Flow, felt behaviorally involved and empathized with each other, finding it enjoyable to play the game together. Key words: Multi-Brain Brain-Computer Interfaces, Games, Steady- State Visually Evoked Potentials 1 Introduction Initially, Brain-Computer Interfaces (BCIs) primary goal was to restore commu- nication for the physically challenged. Applications include moving a wheelchair [1], spelling through a device [2], among others. However BCI devices are progres- sively becoming smaller and more affordable. Easy-to-use Electroencephalogra- phy (EEG)-based BCI headsets such as the Emotiv EPOC or the NeuroSky s MindWave have appeared in the market, leading to their usage outside the med- ical field and towards healthy user industries, like entertainment. In particular, the gaming industry is embracing BCI as an acceptable interaction modality given its potential to enhance user experience by offering something that cur- rent interaction modalities do not [3]. Among the BCIs implemented for games, the first trend was to adapt previ- ously made games conceived for traditional inputs. Classic games like Pacman