GemCraft: Chapter One - The Forgotten

Description
GemCraft: Chapter One - The Forgotten is a tower defense game set in a fantasy world where players assume the role of a young wizard on a quest to confront an evil wizard in the east. This antagonist has released monsters across the land, and the player's mission revolves around clearing towers of these creatures using gem-powered defenses.
Gameplay is centered around the creation, combination, and strategic placement of magic gems in towers so that they can fire at passing monsters. These gems, integral to the player's defense mechanisms, come in eight types: Poison, Triple Damage, Splash, Slow, Chain Hit, Steal Mana, Reduce Armor, and Shock. Each gem's color designates its ability, while its rank determines the power and range of its attacks. In addition to being placed in towers, gems can be fused to enhance their abilities, or used as "gem bombs" to damage nearby enemies. If monsters breach the player's defenses and reach the tower, a "banishment" mana cost is incurred, sending the monster back to the start of the path. If the banishment cost cannot be paid, the player loses the level.
Mana plays a vital role, used for various purposes including purchasing and merging gems, erecting new defenses, and acquiring mana upgrades. As players progress, they earn experience and can achieve special accolades known as "amulets" to boost their scores. Leveling up provides skill points, which can be spent on various upgrades such as increased initial mana, quality of starter gems, etc. Previously played levels can be revisited to earn additional experience.