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This game is playable on Windows.This game is playable on macOS.   This subject is from the Portal era.This subject is in the Real world.
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Portal: First Slice is the official demo version of Portal.


Portal: First Slice consists of test chambers 00-10, with a total of 11 test chambers.

It was originally available on Steam for any user with an Nvidia graphics chipset. The demo was distributed along with Half-Life 2: Deathmatch, Peggle Extreme, and Half-Life 2: Lost Coast.

After some time, it was eventually made available to all Steam users, before being completely removed from Steam during the "Portal is Free" marketing campaign.

It is now back on Steam again, and available to everyone on Steam for free.


  • The origin of the title First Slice, is a reference to the cake that GLaDOS proposes to Chell, what was thought to be a major ruse, and was turned into an internet meme, but was seen later in the game.
  • The name may also refer to the video game development term "vertical slice". Vertical slices are small but extremely detailed demonstrations used to pitch the game to a potential publisher. Like development levels, they are usually only available to the company making the game.
  • Test Chamber 10 appears to be cut-off with a NODRAW block, leaving the player to exit the game.(NOTE:Test Chamber 10 will no longer be cut-off with a NODRAW block)

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