I wonder why one would scale the particle system on the Z axis for a 2D environment.
Also, 70x70 is almost 3 times as large as the area covered by the scene, so I sue hope the Culling Mode “Automatic” can work with that…
I did think it was rather large as well but i think Stephen wanted to be sure it would cover the entire area.
I did see your post in the show section on moving the twinkles with the player.
I think the scaling on the Z axis is just habit from scaling all axis as the camera is in orthographic mode so it does not care about the Z axis but it may help with the dispersal of particles within the space.