I don't see how this is a donut topology. If it were you could move off the sides and end up on the other side of the screen. Like Pac-Man or Asteroids.

It's analog because you can move any continuous distance. Not just a discrete number of tiles.

In regular chess you can only move discrete distances (1, 2, 3 squares, etc.) - this is analogue in the sense that pieces can move continuous distances.