The most crucial thing here is being emotional. Writing is emotional per se. So it should work. Even anger makes you a better writer than calmness.
A must read: Writer’s Block: 27 Techniques to Overcome It Forever by Henneke Duistermaat
Freewriting or brainstorming often helps me a lot. The core reason for a writer's block is the so-called "conflicted feelings phenomenon" and that's where each fiction writer finds himself bewildered and dismayed. Whenever I have doubts or feel like I failed the writing style or my techniques...
Yeah, I agree, the end was a bit rushed, but that was necessary I guess. As a storyteller myself (fan fic and short stories, mostly), I often choose this variant, I mean when there's a chance to dwell on the events/elements more in next narratives.
I'm so excited about Kingdom Hearts!