Sleep Swimmer is a 2D cozy game where you float around an underwater world making friends with salamander people and collecting sounds to mix on your DJ set. At its core, Sleep Swimmer is about dealing with overstimulation. The player character, Aria, is a girl who is consumed by anxiety due to being overstimulated by the over-connectivity of the modern world. In her dreams she swims around an underwater town called Salamanderville, where she meets salamanders who are having a similar problem: There's an awful sound that pollutes the audio-sphere of their marine world, overwhelming everyone in town. The noise seems to come and go, but the mystery remains: what is causing this sound and how can we stop it?

Gameplay revolves around exploring the town and surrounding areas, interacting with unique characters, making music with the DJ mixing mechanics, and uncovering the story of Aria and the salamanders. Players swim around this lush, vibrant aquatic world and collect sounds, mix them on their DJ set, and make friends with the salamander townsfolk.

The DJ mechanic involves a UI DJ panel that mimics a simplified mixing deck in order to make an accessible music making tool for people that aren't necessarily skilled or knowledgeable in music making. This mechanic gives the player a sense of mastery as they collect sounds then mix them together within the DJ system.

Sleep Swimmer’s goal is to be a comforting escape from overstimulation through its relaxing gameplay and relatable and charming story, while stunning the player with its quirky and fun visual style.