Thanks for the feedback. Nice to see that you enjoyed playing the game.
There is an audio feedback for the sliding door. We have masked it (layered it) with the sound of doorknob so that it isn't immediately obvious.
The ability to walk around after the credit wasn't a design choice when we were developing the game loop but when we encountered it we decided to keep it. Just like you said it contributed to the overall game well.
We will definitely take a look at your game.
-Kunal