If you have the gate key you can go to the backyard on the ground floor all the way to the left and there you'll get the end game. Currently that is where the game end but we are planning on expanding and adding a few missing dialogues that change deppending on the order you interact with events and the neighbours.
I was able to go out that door on the far left right away at the beginning and I died. Is that a bug to be able to leave without the key? but thank you for replying! I thought I was missing something important that was supposed to progress the game further. I am really excited to see how the story progresses and the relationship with the boys go.