Collecting All Heart Containers:
To achieve 100% completion, you'll need to collect all 16 Heart Containers. Four are obtained from bosses, and the remaining 12 are found through side quests, mini-games, and hidden chests. Refer to the 'Side Quests & Activities' section for specific locations.
Maxing Out Spirit Gems:
Collect all Power, Wisdom, and Courage Gems to fully upgrade Ciela's abilities. This requires thorough exploration and completion of many optional challenges. There are 20 of each type of gem, for a total of 60. Each set of 10 gems provides a new level of upgrade.
All Ship Parts:
Gathering every unique ship part is a significant undertaking. This involves extensive salvaging, winning mini-games, and trading with NPCs. Aim to collect full sets of each material type for the best defensive bonuses and a complete collection.
Completing the Treasure Map Collection:
Find and use every Treasure Map to retrieve all sunken treasures. This will lead you to many valuable items and Rupees, contributing to your overall completion.
Fish Collection:
Catch every type of fish available in the game. While not always directly tied to a percentage, it's a common goal for completionists and can lead to rewards.
Sound Test:
After completing the game, a 'Sound Test' option becomes available on the title screen, allowing you to listen to all the game's music and sound effects. This is a small but satisfying reward for finishing your adventure.