There's some overlap here with the therapy technique called EMDR (used to treat acute PTSD). Both EMDR and the Tetris study involve thinking about the traumatic event while experiencing bilateral stimulation.
Studies on bilateral stimulation look really promising as a tool to manage trauma:
I haven't considered Tetris, but I'm researching the effects of Osu! (a rhythm game that requires heavy eye-movement and tapping) on people's public speaking anxiety. I can pretty conclusively show that people who stream with the tag "Depression" and "Anxiety" on Twitch speak considerably more while playing Osu! compared to other games - sort of like this paper but with live streamers https://pubmed.ncbi.nlm.nih.gov/26100455/ - my interpretation of my data is that people streaming with tags that suggest they are more likely to experience speaking anxiety, speak more while playing games that require heavy bilateral stimulation because they are desensitized to their anxiety.
Is there anyone else looking at or any other material on the subject of EMDR + video games? I can't find anything on the subject, which is kind of ridiculous considering how obvious the link is.
A theory I found plausible was that EMDR was the brain rewarding you for moving away from a stressful situation, and the eye darting is something you do while moving through a physical space.
This made me think of the various games that move through 3D space. Interesting that Tetris also triggers this.
Studies on bilateral stimulation look really promising as a tool to manage trauma:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5061320/ (note the before / after section)