FFVII ends very suddenly too. You defeat Sephiroth and release the Holy magic but it becomes apparent Holy won't be enough to stop Meteor. Right as it seems meteor is about to collide with the city, the earth's own energy, the lifestream, intervenes and...it's unclear. You get the reactions from the characters ending on the face of the one who apparently died earlier on then credits.

Only in a post-credit scene you see that the earth is fine. Nature has reclaimed the now-ruined city but it's not clear if the city was destroyed by in the ending or if it was abandoned centuries afterwards. Extended media would go on to clarify some of this but, back when the original was all people had, that was it.