Portal, on the other hand, presents a fittingly warped view of the scientific process, embodied by its artificially intelligent main character. GLaDOS is more than just SHODAN with a better speech synth and a taste for pastry. Even after the destruction of her lab and the world outside, she keeps running her bizarre tests, to the point of cannibalizing the Aperture workforce for subjects. What hypothesis could giving her prisoners a portal gun and making them bounce around increasingly deadly environments possibly prove?
The answer, of course, is nothing. Where Black Mesa's scientists keep striving for the betterment of the species, GLaDOS is the nightmare side of industrial science - pointless, commercialized and needlessly competitive for resources. It would be a mistake, surely, to read too much into the game's absurdist narrative, but I can't help but wonder about the subtext: it's the same kind of corporate research that brought us the McDonald's "shake." Still I note, hopefully, that the portal gun itself is never seen as intrinsically evil. Even GLaDOS herself is a figure more tragic than sinister. The technology that creates her is no Frankenstein or Pandora's box; it just doesn't actually understand the principles of discovery and revelation that have driven scientific progress since the Renaissance.
Half-Life's fans could have likely guessed at a lot of developments in the sequel - the presence of the G-Man, the return of the standard weaponry, Gordon's voiceless interactions with other characters - but I don't remember anyone ever predicting players would spend at least half their time flinging heavy objects around with the gravity gun, although it's fitting that Gordon can push much larger carts in the second game.
It is, in fact, the bizarre nature of their weaponry that has also made both Half-Life 2 and Portal such odd examples of shooters, so much so that the latter barely seems to qualify. But while the gravity gun lets Gordon Freeman interact with his environment in a semi-realistic way, the Aperture Science Handheld Portal Device is noteworthy in part for the way it turns the physics engine inward. Instead of being able to toss cars and barrels around like the Incredible Hulk, Portal asks the player to set up situations and let the physics do the work, even acting on his own body.