http://content.hl2p.com:8080/videos/tra ... r_720p.avi <-- Better Quality trailer off the official site:
http://hl2p.com/home/ .
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Portal is a game recently announced by VALVE which will be released with Half-Life² - Episode Two in either a standalone or built-in form. Valve has taken a step forward in game innovation by giving users of the game Portal the opportunity to seemlessly create dimensional doors to teleport you from one place to another.
Players use a tool called the “Aperture Science Handheld Portal Device” which creates portals on the fly. You read right - a gun that creates instant openings through walls that transport you to another place.This concept can be applied to many game types.
As of now it looks like Single Player will be the only game type included with this game, but that doesn’t leave out multiplayer mod opportunities. Puzzle maps would seem to be the most logical route for this style of gameplay. As seen in the first trailer released by VALVE, where you could not normally reach your destination by walking or running, you now can with the portal tool. This opens a gateway to countless possibilities of fun-filled gaming"