I don't find the study to be very convincing. Why the participant willingness to help was not assessed before the exercise? Without measuring this and showing improvement due to the game there is no way to know whether the VR really improved the willingness to help.

As it stands looks like a very fancy experiment on a very small number of samples, lacking any statistical power, yielding marginally significant results that at the end means nothing. Too bad, it could have been easily a great study. Another idea to the researchers, IF there is really a tendency to help after playing the game, how long does it sticks?