hint for graphically challenged computers use vertex shader or quick rather than pixel shader for scene preview
avoid trees, grass and water and render to image series if needed (sound needs readding)
it could crash your graphics card otherwise, I had this a lot on my 2GB RAM craptop with intel integrated graphics, it just crashes the program, no serious harm but you lose your work, I learnt to work around it.
used backgrounds a lot
you can do just trees and render them on planes as png and add animated if needed etc