That's intentional. :'D
If I ever do a future update, maybe I'll put something there so people know it's not a bug. Or at least put a credits scroll or something. >~<
I see all the other commenters got it, maybe it was me too stupid to get it...! However from my point of view I was quite intrigued until I felt trolled... Maybe it doesn't matter talking since it was just a speed project but if you'll ever do a "serious" project I suggest to pay more attention on the way it closes.
PS: The voice acting was a pleasant surprise, but maybe next time you should consider to have a voice for the narration part too.