Sea of Stars is an adventure role-play game about two children of the solstice. It combines turn-based combat, storytelling, exploration and interactions with the environment all in a pixel art style. Unusual for a role-play game, Sea of Stars also offers platform-style traversal. You swim, climb, vault, jump off or hoist up ledges to get around. This offers a nod to the developer's previous game, The Messenger, to which Sea of Stars is a prequel.

You choose between six unique playable combat characters, each with their own backstory, personal objectives, play style, special skills, and synergies with the rest of the party. In turned-based battles, you still need to pull off timed button presses to gain offensive and defensive advantages. Along with timed hits, combat features multi-character combo attacks and boosting from the different characters in your party. Again, unusual for these types of games, the battles that happen in the main game world aren't random encounters. You can always see them coming and decide whether to engage or not.

As you progress you meet dozens of characters and slowly discover an interwoven story. It's a combination of tongue-in-cheek silly while retaining a sense of epic saga. There's also time in the game given over to slower-paced play: sailing, cooking, fishing, and stopping by a tavern to listen to a song. The result is an adventure about friendship and unexpected twists.