What you describe is not called PTSD, it is Game transfer phenomena (GTP) or Tetris Syndrome. It happens to a lot of people and for many different kinds of games. Hypnagogic imagery such as seeing pixel artifacts, sliding movements, flashing or strobing are quite common. People can even feel sensations like moving, spinning or falling in combination with hallucinations.
Feel free to chalk this up to video games being more like LSD than we are willing to admit.