Where can I "downdate" Alphas?

[Gordon Freeman]

I'd like to revert back to older Alphas, but I don't remember how. I recall it having to do something with going into US2's properties in the Steam Library, but I don't know where to go from there.

[Jar]

Yep, right click on Universe Sandbox ² in your Steam library, then select Properties. Click on the BETAS tab and from the drop down menu you should be able to select older alphas.