Every time I see someone comment on that effect it makes me giggle a little inside...
Geforce effects was something we had internally in the early alphas but was never really meant to be released - we pushed the limits out to where ships of the time couldn't trigger it and then forgot entirely until faster ships and flight model changes made it attainable again... debug colour-overlay and all. We could remove it but it's become an accidental feature I guess

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For anyone interested the current limits are 18 negative G to start a red-out and 25 positive G to start a blackout, if you hold it for 4 seconds above that limit you'll lose control. Sustained for a while that would not to good things to a human body/brain!