Make sure you are using the same email you used when bought the game.
Download the Itch.io app (https://itch.io/app)
Log in.
You should see a hub of all PURCHASED GAMES.
Right-click "That's Not My Neighbor."
Click on "Check for updates."
Download the update.
Alternative option:
Uninstall "That's Not My Neighbor."
Download the Itch.io app (https://itch.io/app).
Log in.
You should see a hub of all PURCHASED GAMES.
Redownload "That's Not My Neighbor."
The updates should automatically download.
If you encounter any issues with the game, please check this vlog: https://nachogames.itch.io/thats-not-my-neighbor/devlog/708650/read-if-you-have-...