In Grow Castle Defense, as you fight them, the threats of the pal world change. Get coins for every enemy you kill, and you'll get stronger.
Improve your shooters and swordsmen. Speed up the process of making money. The bad guys you fight will get stronger as you level up. Every five levels, you'll face an enemy from the pal world. Kill the big boss baddies to get extra money. Every so often, you will be given new skills. These skills are triggered automatically, and the way you interact with them changes how they work. If you click the mouse, you can move it.
Have fun and good luck!