Thank you for playing our game! I'm hopeful you mean you were able to find the ending quickly and not that you ran into a game breaking bug! I will definitely say that the ending is more sudden than I would've liked; we ran out of time at the end of the jam and had to cut a lot of stuff we intended to include. :(
There definitely is a use for the green key, although there is also a way to bypass the need for it, so it's possible you didn't find its purpose during your playthrough. It doesn't open the weather station though -- but good guess. ;)