Why does the application only work with the Live Server extension?

I was running a project for a game similar to Mario using the Kaboom.Js library, I finished the project and everything was ok. But when I run the project through index.html the complete game does not appear, but rather the texts from the game scene, but if run with the Live Server extension in Vs code it works perfectly as it should. Any way to resolve this?

repository: https://github.com/isacpxc/mario-kaboomJs-3000 (just open the folder with vscode and run Live Server on index.html and it will work. The same does not happen just by clicking on index.html,)