"Playable alpha" refers to a preliminary version of a video game that is still in development. It is a test version of the game that can be played by users, even though it may lack certain features, have bugs, or need improvements. Full definition
The studio has already attracted enough funds to get the game into alpha status, and has released playable alpha versions of the game on the PC. (nintendotoday.com)
There is a fully playable alpha test version freely available for download. (fractilegames.com)
Its legacy is a lasting one; the newest installment in the series is currently in playable alpha and is expected to release sometime this year, while the current iteration of Unreal Engine 4 is being used by developers to create even more beautiful worlds. (gameluster.com)