Day 1: Purchase as many mines as possible. Place them on the back row, then detonate them when a few enemies are near. Day 2: Same as Day 1. Day 3: Same as Day 1. Day 4: Same as Day 3, except save the mines for the cars to make sure they are destroyed. Day 5: Same as Day 4, except use the suicide drivers to destroy enemies that are near them in order to save mines. Day 6: None.