We have confirmed an issue in which a specific key item (name omitted to avoid spoilers) is not properly added to the "Key Items" list, and this issue is planned to be addressed in a future update. This particular issue is caused by swinging your knife between the time that Chapter 12 starts and when the key item is displayed on the upper-right corner and added to your "Key Items" list. Due to this issue, it becomes impossible to progress later on in the game.
At this time, please ensure that you do not swing the knife during this scene. If you have run into this issue, we recommend you restart your game from an earlier save data before obtaining the key (before Chapter 12). If an earlier save data is not available, the game will have to be restarted from the beginning. We apologize for the inconvenience.
UPDATE April 23rd, 2023
An update has been distributed as of April 23rd, 2023. We encourage all players to install the update before continuing to play the game. Those that have run into the issue should now be able to continue to play the game normally.