This is gonna sound weird, but Deltarune reminds me of The Fifth Element in how it was made.

>Teenager had a dream
>wrote all his shit in a little notebook through school
>never gave up on it
>did smaller scale stuff to get funds
>eventually pitches the script
>issues
>Catches the eye of Bruce Willis in his prime and other top actors
>They take paycuts, especially Bruce because they fell in love with the idea
>Creates his ultimate childhood dream