All of these papers - the research in favour, against, cited in the review, and the review itself - have at least one of E.A. Holmes and E.L. James, as authors, and most have both. I'd want to see solid independent replication of this result before giving it too much credence.
https://pubmed.ncbi.nlm.nih.gov/28348380/
This is a later study which found Tetris had no effect:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8366629/
Here's a review which cites four papers as supporting the effect of Tetris:
https://www.sciencedirect.com/science/article/pii/S027273581...
All of these papers - the research in favour, against, cited in the review, and the review itself - have at least one of E.A. Holmes and E.L. James, as authors, and most have both. I'd want to see solid independent replication of this result before giving it too much credence.