Butter a 13' X 9" pan. Can spray with Pam or other cooking spray, also.
Melt butterscotch chips and peanut butter in large pan over low/med heat, stirring constantly. Remove from heat; add in rice krispies cereal, making sure it is well coated.
Using half of the cereal mixture, place into prepared pan, pressing firmly with buttered hands. Set in refrigerator until chilled.
In small saucepan, melt chocolate chips, butter, & water together over low/med heat, stirring constantly. Remove from heat & stir in powdered sugar, mixing completely. Spread this mixture over cereal layer in pan.
Top with remaining cereal mixture, again pressing firmly. Return to refrigerator to chill well. I score it before chilling because it is harder to cut when real cold.
NOTE: I have substituted milk choc in cereal mixture, p.b chips for filling; also milk choc in cereal, mint flavor chips for filling; p.b. chips for cereal, milk choc for filling; I know someone who used Heath toffee bits in cereal mix & milk choc for filling...was yummy! You could also use the Andes candies for filling instead of cooked filling, but takes a lot to completely cover the pan. Use your imagination!! Possibilities are endless!