Or "Hope of Shané" (I insist on that accent, otherwise I may have to rename her "Shanei" just to get people to pronounce the name right) could get a full-on remake in its own engine.
Something like, "nine games for the price of one", haha. Plus new AIs and stuff to keep it fresh rather than TOO Cave Story-ish. (Or "Very Tacos", but Mejuffrou Fortuin hates that. :p )
But that's Aeonian Works talk, plus I had a sequel in mind that ties all the versions together.
> RUN
> user/works/aeonian/hope/frost.exe
> FILE CORRUPT, CONTINUE?
> yes
> ERROR: CANNOT FIND "heroine.ltb"
> CONTINUE?
> yes
> STARTING PROGRAM...
> WARNING: SPRITES FOR ENTITY "HEROINE" CANNOT BE FOUND. CONTINUE?
> flower dragon
> COMMAND NOT RECOGNIZED
> SELF-DESTRUCT SEQUENCE INITIALIZED
> HAVE A NICE DAY :-)
Hope of Shané, sorry. That mod could become it's own game and all 4 versions being selectable in a single game would give it a lot of replay value. New A.Is is pretty much a given because of all the things you'll get to do outside of Cave Story's constraints. Also the sequel after Hope of Shané would also be interesting once you get there.
(* A giant explosion happens. You see shrapnel on the floor. Also a flower dragon eating a loaf of bread. :3)