Cut cake into cubes and place in the bottom of a 9 x 13 pan, squeezing cake together to fit into one layer. Drizzle the alcohol over the cake, if using.
Prepare the chocolate pudding as directed on the package using 2 cups milk. Pour the pudding evenly over the cake.
Whip the cream with the sugar until firm peaks are formed, do not overbeat. Spread the whipped cream evenly over the pudding.
Crush the candy bars between wax paper using a rolling pin. Cover the whipped cream completely with the crushed chocolate bars. Drizzle melted chocolate using a spoon over the topping in a criss cross pattern.
Refrigerate several hours or overnight before serving.