Explain the statement'everything that i ve described is true virtually'?

The narrator says that whatever he has described in the various versions of the games is true.It is "virtually true".what is virtual reality? Images created by a computer appear to surround the person looking at them.and they seem to be always real.interactive psycho-driven games like 'widwest','dragon quest','jailbreak' give virtual real images.even the theory of sebastian's memory being saved in computer and finding its way into the games are 'virtually true'