Note: setbackpal is BAD BAD BAD BAD BAD BAD -Shoots it-
Do not use this command. Ever. Ever! Or behold the wrath of Rabid's projectile kitties!

(Don't ask)
Anyway, use seteffect(red,green,blue,alpha);, all numbers are between 0 and 1, and Alpha is the darkness of the level. Fiddle with it! Set all four values to 0 to reset it.