A Cold Heart is a short underwater-themed shooter where you play a cold-hearted mermaid, out to take the lives of ten different sea creatures by singing for them with your beautiful voice. You start out with three hearts that represent your well-being, although you there are ample chances to replenish them after every boss fight.

The ending is very anti-climatic, so don't expect too much out of the game if you don't want to end up being extremely disappointed by it.