Optimization?

[The chaser]

In the level editor, at the side of "File" (where you load, save the maps, etc) there's a panel called "Edit". Click it, and, at the final, there's something called "Level Settings". Click it, and go to "Fog". Tick the "Active" box and play with the color and Start/End values. I like to have the start to 10/20 and the final at 40/50