Alpha

From Styleguide

alpha

An early, incomplete version of a game. Alpha code is typically missing important features or functions planned for the final game. An alpha version is often considered an important benchmark in software development as it indicates that the core of the program is working and ready for testing.

An alpha version can be referred to simply as an alpha on all references. Do not refer to a version of a game as alpha unless the game’s developer or publisher has done the same.

Example: The Halo 2 alpha assured office skeptics that Bungie would once again come through with a first-rate game. The alpha code did show some signs of graphical slowdown, which is to be expected at this stage of development.

Wrong: alpha build, alpha game.

Also see: beta.