I think its CS 1.6.
The weapons sure look like 1.6 but the graphics are much worse. Like it was all compressed and limited to 800x600.
I played on several servers and got headshot from impossible distances and angles. There are simply too many cheats and
bots for these games. The Chinese & Japanese gamers will "farm" these servers to death and there will be almost no money
left for the legitimate gamers. I also played some TEXT based MMORPG games before, where these Chinese players dominated
the scene so much, that I stopped playing.

That's why old 1.6 servers employed active anti-cheats that you had to run with the game to be able to enter. I remember that one of them was called cheating death and they had to put up a new version every couple weeks because cheaters were constantly outsmarting it and making new undetectable aimbots.
As for the Chinese they managed to monopolize every game where it was possible to trade and make money , like WoW, Diablo 3, and so on.