Game bugged after putting the postcard together and getting the letters. Now I can only interact with my inventory and nothing else.
A suggestion, it's usually not good in puzzle games when new stuff happens without the player directly affecting it. I accidentally checked the window a second time and found a scrap of paper that wasn't there before. I normally wouldn't have checked again, as I would have assumed it to show up the first time I looked. If you want the player not to find something until after a certain story beat, hide it behind a puzzle instead of just having it appear when you want them to find it.
Also I feel like interaction could have been smoother, instead of having a prompt ask me if I want to check a place out, just let me check it. The prompt just halts the gameplay in a distracting way.
I liked the box puzzle, that was clever. Include more puzzles like that, instead of just having the player search around the room. Good art style, it seems you are well receptive to feedback, so I think you will make some great games in the future.