Its Steam page deliberately sells this as "Slavjank". And yeah, I guess that's what it is -- a janky mess full of bugs.
This FPS was released in Russia all the way back in 2006, pretty much stayed in Russia for 18 years, then suddenly got a worldwide release last year with English localization.
The voice acting is hilarious. And despite all the bugs -- and the greenish-brown colour palette -- there's fun to be had here.