I've heard the ideas it presents dismissed as ripping off Prey, and if there is a more ignorant statement to be made regarding these two games it has yet to be discovered. Prey's portals aren't user created. What's more, they're used in a completely different way: Prey is a first-person shooter, while Portal is clearly... something else. It's a puzzle game, or an adventure game, or a platformer. You tell me.
