At the bottom of page 64 of beta 2, point (2) states: “Instead of inserting the RandomNumberGenerator resource yourself, add Random as a plugin.” This is unchanged from beta 1, should be RandomPlugin to reflect the recent change.
At the top of page 65 it states to remove the RNG resource command, but it doesn’t mention that the ‘player’ and ‘cpu’ functions should both have an input modified to ‘mut rng: ResMut<RandomNumberGenerator>’. After that change, the app will run properly as before.