Thank you Coffee! What a dear this one is.
On the topic:
Cave Story would make an awful movie, no matter what you did it would probably end up cheesy. Because it's a story that would last 6-8 hours, with dialogue and non-rushed expositions. That's why it'd make a better animated TV or Mini-series.
And if anyone's going to write a script for this shit, it's me;
[Enter Balrog, something that I can't describe and will only see in my nightmares]
BALROG:
Huzzah!
???:
...
BALROG:
You don't really look like a rabbit, so, just stay there, while I kidnap this kid.
???:
...
BALROG:
Jesus Christ, guy, would you say something? You're creeping me out.
???:
...
[Enter MISERY, a sexy, sexy, sexy, sexy witch]
MISERY:
Hey, *expletive*head, what's taking so long?
BALROG:
This guy, he's just staring at me.
???:
...
MISERY:
Whatever, kill him
[BALROG blasts ??? with missiles]
THE END.