Hello.
I have Fallout 1, 2 and Tactics.
The 1 and Tactics appears dubbed with the nickname Classic...what does it mean or difference?
But for me they are the same...
I send a capture.

It's essentially the same. "Classic" versions are Fallouts sold on GoG until 2016 and branded as Interplay production. When Bethesda took over, Classic versions were removed from the store (but kept in peoples' libraries) and GoG started selling Bethesda-branded Fallout 1/2/Tactics.

marcosorrit, greetings.

For a detailed explanation, please, refer to this post.