Whether intended or not, a video game has inherently influential messages. I think this is the point that Flanagan is making on critical computer games. Knowing that a game sends a message implies the designer(s) could, and perhaps should, seize the opportunity to shape the messages into something meaningful.
I played Depression Quest recently. This game definitely sends a critical message. The player starts out depressed, not on medication for depression, and not in therapy. Generally speaking, everything is terrible. You have no motivation. Anxiety. Everything bums you out. Work is insurmountable. Relationships uncomfortable. All decisions the game offers are rife with fear, dread, woe, and despair. The music is even depressing.
Eventually you may start therapy, and you may start medication for your depression, but depression keeps coming at you. It’s not over. You do your therapy. You take your meds. But it’s not over. The game ends, but the depression isn’t over. Depression Quest carefully delivers the message that there is no easy solution for depression.