I've used game engines for many years.
Actually, most unused music and sound effects, as well as the main title image and enemy images, can be deleted. However, it's important to note that simply deleting them from the directory isn't enough… You need to locate the map, enemy groups and enemy settings, magic, animations, etc., pages in the system settings and clear all unnecessary settings. Only keep one enemy group, one enemy setting, and one magic effect.
I know a lot about strange occurrences… at least before I suffered half of the body broken bone in an accident, I often shared various experiences and special cases in the RPG community.
Since RPG2003, the biggest strange problem has been "parallel event processing." This is both an engine bug and a player setting issue, mainly due to events stacking and failing to be processed synchronously, or getting frozen in the synchronous processing stage. There's also the classic "clock hard problem"—the countdown system has always been a difficult setting to operate. Ultimately, this leads to incorrect results, either because parallel event processing conflicts cause a soft lock, or because it overrides another time.
Secondly, there's "event processing too fast." This is an old problem, so you must manually add a 0.1-second delay before some variable or numerical checks to resolve it; otherwise, the next event might jump directly before the previous one is finished processing.
Incorrect event activation or stacking is also an old engine problem. If an author creates an event and then directly creates a new event and sets an activation switch or event processing check, it causes the event to lack a pre-check, leading to a bug. In practice, it's best to create a blank page before activating any event. AAAAchan (author of Doraemon: Resident Evil) used numerous blank pages to avoid this bug. Simply put, the first page is empty, a "no event" page; the second page is used to activate the switch or other event triggers.
Another classic bug is the "Gwent effect," caused by globally allocated fixed events. Lazily making events globally triggered results in numerous bugs due to simultaneous calls.
Finally, there's the issue of asset handling. Many careless authors directly modify the game's basic settings but forget to remove default enemy groups, settings, magic effects, map settings, etc., from the settings menu. They only delete the assets in the package directory, not the related settings in the program group… ultimately leading to bugs.
Another less common bug is where level and attributes become "1," the cause of which remains unknown. This usually occurs when player A leaves the party, variables are saved, and player B inherits all of player A's experience, skills, and items.
