Generation Zero supports Streaming Install, also know as 'Play-Go'; meaning that you are able to play part of the game while it's being installed. However, the available map will be limited and will allow single player only.
If you reach an invisible wall by the bridge where you are unable to go further, it means your installation is still in progress. It will take some time to install the game from a disk. If you are downloading the game from the store, it will take longer to complete the download followed by installation.
Once full installation is completed, please backtrack to 'Stenhaga Farm' first, or simply restart the game.
Our team is currently investigating any potential cause that might prevent you from crossing the bridge after installation is completed. In the meantime, there is a workaround by jumping into the water to the left of the bridge. You will spawn on the opposite riverbank and can look for a safe-house on that side.