Assuming the initial version Liana played is similar to this IGN preview4, the flashing effect can cover most of the screen, and I counted ~11 Hz.
Multiple factors contribute to and compound the risk2,3. Though flash rate (#1) and visual field (#2) are the papers’ most mentioned considerations, if meeting one isn’t possible—say for a stage’s front-row audience—further risk reductions include:
I don’t like “The best way to win is not to play”-type guidance, because it implies that no one should ever try. However, putting the work into an intricate chase or gradient pattern can achieve a better effect than simple flashing, so if that’s achievable, seriously consider this mitigation:
All the best to CD Projekt Red and their first week with Cyberpunk 2077’s release. As I was looking for articles and screenshots, I found that this goes far beyond them and this release.
Be good to your users,
1: Harding, G., Wilkins, A., Erba, G., Barkley, G.L., & Fisher, R. (2005). Photic- and Pattern-induced Seizures: Expert Consensus of the Epilepsy Foundation of America Working Group. Epilepsia, 46(9), 1423-25. doi: 10.1111/j.1528-1167.2005.31305.x.
2: IEEE Recommended Practices for Modulating Current in High-Brightness LEDs for Mitigating Health Risks to Viewers, IEEE Standard 1789, 2015
4: IGN preview: https://www.youtube.com/watch?v=KXXGS3MGCro (Warning: Flashing light)