Normal Ending The first stage of Chapter 4, (Hydra Assault) is available from the start of the game but is a daunting 9 star difficulty. Come back and clear it when you think you're up to it, and you'll get the normal ending. You need only be strong enough to kill 3-4 generic officers and peons without getting killed and then the rest relies on your cannon skills.
Good Ending When you've cleared Chapter 3, you'll unlock a new path in Chapter 4, and there will be a branch. The top branch leads to the True Ending (see The Fated Place) and the bottom branch leads to the good ending.
True Ending To unlock this branch in chapter 4, you will need to unlock every playable character minus the Orochi group (Orochi, Shin Orochi, Kiyomori Taira, Sun Wukong, Ne Zha, Susanoo) and then clear the level before it (Orochi Assault) again. This will make the top branch playable and clearing the level in that branch will unlock the final level, (Shin Koshi Castle Decisive Battle). Clear that level and you will watch the true ending and unlock the rest of the playable characters.
I like to use exclamation points!! My favorite punctuation and it just shows emotion!!