What is real? The definition and knowledge about reality differs from person to person.
You could make game from a perspective of a blind and deaf human, just a black screen, and it would be real
However, he would probably see things, since the brain adapts to lack of information. He could probably "see" wind, heat, rain, snow, flowers, sound vibrations, in addition that he can feel them.
But even for a "normal" person (and again, what is "normal"?), some theoretical physicist may see the world completely different than a priest, or an artist. It is said that some people can "see" music, and a priest can probably "see" the work of god and signs of him everywhere. A theoretical physicist might see how the world is made of little superstrings, whose vibrations appears to us like matter, even feel like matter.
And recently some scientists tested if the world is a computer simulation, and the results were positive. Everything what exists, is like in the matrix, there is no sign that anything is "real".
And you can always have a "real" environment, where some billion year old civilizations visit the earth, and let your fantasy play, and it's still "real". Or where CERN invents a stable black hole which allows time and space travel, that's closer to reality than sci-fi.