The reason for that is that the human eye does not have the power to properly expose every single part of what is sees. Your brain actual completes the image based on partial data. With a camera, there is no brain to fix error so you get darkness and over exposure.
By shooting 5 pictures, exposing different areas of the subject and then blending the image you come out with the "perfect" Photograph.
It looks like a video game because drawn images in the games and movies often tend to lack exposure error and that takes away from realism as far as our eyes are concerned.
This is why in movies like Toy Story or Happy Feet, no matter how real the objects are, you tend to always know that there is something not right. They are too perfect.
HDR is the same, it looks awesome!!! But your mind tells you there is something not right.
I did not shoot this Photo.