1. Activate console in steam Enter this in browser: steam://nav/console
2. Paste this command "download_depot 720250 720251 5874631687768504692"
3. After the download is done, Steam will show you where the files were downloaded to.
4. Go to the game's installation directory, and move the files somewhere else. Then go to where the depot files were downloaded to, and move everything over to the game folder.
5. You may have to rename the game's EXE file if the dev changed the launch options recently. You can find the current EXE name by going to the game's SteamDB page and clicking on the Configuration tab.
6. You should now be able to launch the old version through Steam.

IMPORTANT: If you are experiencing the problem where after launching the game you see no menu options this probably means that you have a current patch save file that still exists in your game files. Since these newer patch save files contain more information the old patch game gets confused and breaks. If you delete your save files it should work fine.