The guys at Valve thought they would take a shot at making a new FPS experience for everyone. With the massive success of Half-Life 2, everyone was buzzing with excitement in the air to play Portal, which was a game based ALL on the physics engine and puzzles. No shooting, not story of any sort, just mind bending physics puzzles for people to solve. The result? Pure awesomeness for anyone to play.
Portal really has no story of any sort, but from what I gather, you're a test subject for the portal gun. The portal gun is just like the gravity gun in Half-Life 2, but with the exception that it can create portals. You shoot a blue hole into one wall, an orange in another one, and once you walk through the blue, you'll come out the orange portal. You're goal is to make it through all the levels to prove that the gun is good for the company.
The game play here is amazing. With the Portal gun, there are so many possible ways to solve the many puzzles in the game. Surrounded by robotic torrents? Why not create a portal in the ceiling above them, and then one below a box. Watch the box fall through the portal and destroy the robot below. Or you could make a hole near the door and just walk through it. It's all up to you. The only complaint I have about the game play is that the difficulty shift isn't gradual. All of the first few puzzles are extremely easy, then bam, you walk into a room filled with millions of objects moving and shooting things, torrents everywhere, plat forms, acid floors, and energy collectors hidden behind glass walls you have no idea how to get to.
This game will last you for a long time, especially with the physics puzzles towards the later parts of the game. The game is also hilarious with many one liners that will keep you cracking up. Anyone who plays this game will instantly find themselves in love with it. This game alone makes the Orange box worth the purchase.