In my TD RTS game I have also considered scoring and game play. I intend to have treasure or gold remaining as the score. Purchasing and upgrading turrets will consume this and so will allowing enemies through who will steal some of it if they reach your treasure chest! Therefore it is beneficial for the player to not purchase too many towers which would make it easy if they wish to get a better score. So that not all of the treasure is available from the start, I will try to make it so that the pirates are still digging up all of their treasure at the finish line to allow a gradual release of gold as well as gold given for killing enemies.
