I appreciate you returned to play it again!
The keyhole is hidden in the secret attic of the house, which you can access by jumping on the furniture and climbing the lamp. There’s only a rudimentary end-screen when you open the lock, so there’s not that much to see.
In hindsight I should’ve added a picture of the house in the speech bubble as a final tip.
That was only one of the poor design-choices I made in a hurry, and I’m not surprised you found a glitch I overlooked, so sorry about that!
Don’t know if you noticed BTW but The Moon stops talking if you attack him, and you can actually kill him! (That slightly alters the END-screen graphics)
I had a lot of bigger ideas for the game, but there’s only so much one can implement during a JAM.
Thanks for playing!