Crush the chocolate sandwich cookies into fine crumbs.
Combine the cookie crumbs with melted butter in a bowl.
Press the cookie mixture into the bottom of a 9x13 inch dish to form a crust.
In a separate bowl, beat the softened cream cheese until smooth.
Gradually add powdered sugar to the cream cheese and mix well.
Fold in 1 cup of whipped topping into the cream cheese mixture.
Spread the cream cheese mixture over the cookie crust evenly.
In another bowl, whisk together the chocolate pudding mix and milk until thickened.
Pour the chocolate pudding over the cream cheese layer and spread evenly.
Top with remaining whipped topping and refrigerate for at least 4 hours.