Played a bit on goldsrc.one testing server.

In short, it's a server mod that divides players into two teams, one with Counter-Strike player models and weapons and the other is Half-Life barneys with Half-Life weapons.

It's very fun and even somewhat novel, actually, as I haven't seen server mods like that. To play the game as terrorists, you must join from Counter-Strike client, and to play as barney, you must join from Half-Life respectively.

there are bugs and some (temporary, I hope) workarounds, but nothing that couldn't be fixed from a technical standpoint.