Preheat the oven to 350°F.
In a medium mixing bowl, stir together the finely crushed pretzels, melted butter, and sugar until the mixture is thoroughly combined.
Press the pretzel mixture evenly into the bottom of an ungreased 9×13-inch baking dish to form the crust.
Bake for 10 minutes only, taking care not to leave it in longer, as overbaking may cause sticking. Set the dish on a wire rack and let the crust cool completely.
While the crust bakes, bring 1 cup of water to a boil in a saucepan. Pour the boiling water into a large heatproof bowl, add the pineapple gelatin, and stir until fully dissolved.
Add the crushed ice to the gelatin mixture and stir until the ice has melted completely.
Drain the crushed pineapple thoroughly by pressing it in a strainer with a spoon or spatula to remove as much liquid as possible. Stir the drained pineapple into the gelatin mixture.
Place the pineapple gelatin mixture in the refrigerator for about 15 minutes, or until it begins to thicken slightly and is partially set.
Meanwhile, prepare the cream cheese layer by combining the softened cream cheese, whipped topping, and sugar in a large bowl. Beat until the mixture becomes smooth and creamy.
Spread the cream cheese mixture evenly over the cooled pretzel crust, smoothing the surface carefully.
Gently spoon the slightly thickened pineapple gelatin mixture over the cream cheese layer, distributing it evenly without disturbing the layer beneath.
Cover the dish and refrigerate for 4 to 6 hours, or overnight, until fully chilled and firm.
Cut into squares to serve. Garnish, if desired, with additional whipped topping, drained pineapple pieces, and fresh mint leaves.