In video games development, and more broadly in software development, Alpha state refers to a feature incomplete and largely untested state and is unrelated to internal/external sales, review, testing or release.

Alpha software is not thoroughly tested by the developer before it is released to customers.

While outside of recent trends, particularly in crowd funded games development, alpha releases to customers for paid software are less common they do occur and don't have any bearing on the alpha state of the software.

In general, external availability of alpha software is uncommon for proprietary software, while open source software often has publicly available alpha versions.

Further

A feature-complete (FC) version of a piece of software has all of its planned or primary features implemented but is not yet final due to bugs, performance or stability issues. This occurs at the end of alpha testing in development.

And for Beta

Beta, named after the second letter of the Greek alphabet, is the software development phase following alpha. A beta phase generally begins when the software is feature-complete but likely to contain several known or unknown bugs

I am both a qualified software developer, and have worked in the video games industry. I hope you have learnt something.

https://en.wikipedia.org/wiki/Software_release_life_cycle