This is a fictionalized story of how Tetris left the Soviet Union and became a worldwide phenomenon. How fictional I don’t know as I haven’t read much on the fact-based side of the story. I see there is a documentary out there featuring many of the people depicted in this film version, so that might be interest to watch.
But this slice of entertainment is fast-moving and engaging so I would forgive it for any slight lapses in accuracy. Oddly, when I first watched it the subtitles weren’t working and with all the languages and interpreting going on, it took me a while to realize I was missing dialogue I wasn’t supposed to miss, so I started over after making sure the captions were there. So yes, you do need the captions to get the entire story.