I can honestly say that "Portal" is definitely superior.
Ahahahahahaha, Portal's main concept is... portals! and that was stolen from Prey. Add some stolen cliches like a pet companion cube (pet rock?) or the cake is a lie (there is no spoon) and mix it all up with targeted brainwashing marketing for a couple months and you got a full fledged game.
On a side note: Valve sucks at making games, they only release a SDK, let people make mods and then buy them. If it was'nt for the quake engine half-life would'nt exist or be famous at all, and even if it did they would have died soon without Counter-Strike.#Q&_^Q&Q#LINK:86#Q&_^Q&Q#
Wow, um, I'm just going to deal with this part, first, Portal was created by the team Valve hired after they saw their game Narbacular Drop, which is a similar portal puzzle type game. ND was released a year before Prey. And the big thing about Portal is its absolutely mind-bending puzzles, things like portaling 10 feet in the air to drop into another portal, so you can get high enough to slap a portal somewhere else. Preys portals are not used in nearly the same way (from what I have read, at least). Basically, its like saying that Tolkiens books and the Warhammer 40k books are completely the same, because they both fight orcs. And the companion cube has nothing to do with a pet rock, and "the cake is a lie" is literal, as you were promised cake. "There is no spoon" is about the world actually being all an illusion, which it isn't in portal (or if it is, it is, as Grin from The Mighty Ducks: The Animated Series would say, "An illusion that really, really hurts" :) ) Also, the idea that Half Life would have died without counterstrike is absurd, as Half-life was a runaway success long before CS came around. As well as the fact that Half-Life 2 and the episodes sold like hot cakes, even though you have to buy CS:Source seperately ( so no ones buying them for CS of any type). And so they used the quake engine, most games use an engine developed by someone else, as engine development is VERY VERY expensive.
Anyway, on todays games, I'm calling Sturgeon's Law "90% of everything is garbage". We just don't remember the garbage (Anyone remember Bubsy the Cat? Anyone? And of course we can go back to the original Atari with the infamous E.T.(I've actually played that, hugely annoying))