Just on the previous page, user ПочтиПРО shared his problem with us, also encountering unknown issues when trying to play the latest version of the Campaign, but he managed to solve them by clearing the save folder. But, before resorting to such a drastic solution, I can suggest simply creating a new in-game profile.
Added 14 minutes later
I looked into it... ПочтиПРО initially tried to launch the game using the H5_Game shortcut... he didn't need to delete anything, he just needed to launch the game using the H5_Game.NCF shortcut (which he later did). In addition, after he uninstalled the game, he reinstalled the Remix version, and the Walkthrough was for a version earlier than the latest 1.3 update