This is a prequel to Gem Craft
. It's an advanced TD game just like the first part. You build towers along a path to stop monsters that use this path to reach their target. Your goal is to kill these monsters before they do it. The towers themselves don't harm the monsters. You need to make gems and put them on top of the towers. There are gems of different colors and shapes. The shape represents the power of the gem and the color signifies the specific attributes of this gem. Apart from special effects of the colors, the damage called by a gem depends on how its color interacts with the color of the enemy it's shooting. You can join gems together. They create a gem of a higher grade while their color is mixed (unless both have the same color). The higher level gem inherits the effects of both gems it's made of.