Board Thread:Questions and Answers/@comment-73.35.140.143-20140811021817/@comment-24826155-20140817014834

My guess on why the Dartling Gun, Ace Monkey, and Banana Plantations restrictions on Cave terrains is that the Dartling Gun's constant shooting of darts would topple the cave walls if it hit the walls, causing a cave in, the Ace Monkey can't fly in caves due to the low ceiling (Not shown in the Tower Defense mode, of course), and Banana Plantations couldn't grow bananas due to the little light in caves.