I like this article, but not sure if it is healthy to equate mental serenity and success whilst killing "Evil" / dehumanised figures in a simulator as anything spiritual.
A question that comes to mind is what was making the decisions on which parts of the brain to "switch on and off" via the head attached probes? Was this an external controller, and if it was, could it even have been part of the script controlling also the simulated "baddies"? If so, then why would the serenity experienced not have been down to feeling less responsibility for the things happening? Being controlled like a drone would probably be a similar experience.
In any case, spirituality to me means being at ease with one's own "soul", or subconscious. I don't think that can come from killing, simulated or otherwise. Probably the opposite actually, the soul dies and we become inhuman ourselves when we dehumanise others.
So to me the serenity or calmness experienced had nothing to do with spirituality, it wasn't a good thing, to be killing in even more cold blood like a machine, simulated or otherwise.