Evaluating a VR Game Featuring Optical Illusion Challenges: A Study on Workload, VR Sickness, and User Experience

VR gaming is rapidly growing in popularity, with puzzle-based games featuring optical illusions attracting gamers attention. Optical illusions are an emerging gameplay mechanic, challenging players' perceptual and cognitive abilities. While widely used in 2D/3D games, their integration into VR remains underexplored. This study investigates the use of optical illusion challenges in a VR game, focusing on players' workload demands, possible onset of VR sickness, and overall experience. A not-so-serious educational game featuring optical illusion challenges as core tasks for progression was developed for VR and PC, and a comparative evaluation was conducted. Results revealed that these challenges provided an enjoyable and immersive experience, with generally low workload demands. However, the complexity and disorienting nature of some illusions occasionally increased physical and mental effort, triggering VR sickness in some players. These findings offer valuable insights for designing VR games, highlighting the importance of balancing challenge and comfort when implementing such mechanics.