I’m glad to hear you’re enjoying it! 🙂
The place where you’re stuck is an (intentionally) cliched puzzle that
has been used in a lot of adventure games. I think Phantasmagoria
did it first. Look inside the keyhole (it’s a little hard to
find, so keep an eye on the bottom of your screen to see the word
‘keyhole’ when your cursor is positioned in the right place).
There is something inside the keyhole that you have to get out.