Once a boss is defeated, it will be available in Boss Attack Mode. You can take on any boss you wish without going through the level. Complete the game and "All" will become available allowing you to take on every boss one after another. Unlockables Boss Attack Once a boss is defeated, it is available in Boss Attack Mode, where you can freely select which boss to take on. Complete the game and you unlock "All", where you can play through each boss in sequence. Unlockable How to Unlock Ace Ranking Replays Each level completed unlocks the Ace replay for that stage. Free Play Complete the game once (any difficulty) Gallery Mode Complete the game once (any difficulty) Ship Model View Complete the game once (any difficulty). This mode allows you to view all major ships in the game. Contributed By: GrAyEeWoLf.