You may have a faulty/scratched disk. Order a new one or ask for a replacement if it was delivered to you in that state.
Kindle help me to answer What is valve point loading effect and its applcation
Once in a while, Valve will have portal be free for a while.
Valve Corporation did.
Valve
The video game portal is developed by Valve Corporation, also widely known as Valve. The Valve Corporation was formerly known as Valve Software. Valve was made originally made famous by it's Half-Life video game series.
A valve (device) to regulate flow to prevent over loading a system
You cannot get a demo for Portal 2, and if there were it would be on Steam as Valve (the creators of Portal 2) distribute all their games there exclusively. However, if you haven't played the first Portal game I would recommend it, and if you like it you'll be sure to love Portal 2!
Maybe Im Not Sure If Valve Will If They Do Atlas and P-Body They Wont Be In It
Valve, the same maker of Left 4 Dead.
the next valve game coming is the portal 3 half life 3 thanks for asking and have fun on the game bye for now
Portal is a single-player Puzzle-Platformer developed by Valve Corporation.Developer: Valve CorporationPublishers: Valve Corporation, Microsoft Game StudiosDistributors: Electronic Arts, SteamComposers: Kelly Bailey, Mike Morasky , Jonathan CoultonSeries: Half-LifeEngine: Source (Source is a 3D game engine developed by Valve Corporation)If your asking if it runs the Source engine here is your answer.
No