I believe you're correct, and the Half-Life wiki seems to support that: https://half-life.fandom.com/wiki/Black_Mesa_(game)

Oh, sorry, you are correct. My brain melted a bit in a heat :)

Yes, but with several asterisks.

* Graphics are better (this should not be a surprise)

* Some maps have been made shorter (the underground railway tunnels, if my memory serves)

* The last part of the game (Xen) was pretty much completely overhauled, and in my opinion, improved.

This is from memory so I might be getting one or two details wrong.