Hello @geometry dash scratch, I think the error message "Cannot GET /dist/" typically indicates that the server is unable to locate the specified directory or route. In this case, it seems that the /dist/ directory is not being served correctly.

To resolve this issue, you can try modifying the URL to include the demo name before the /dist/ path. As you mentioned, some themes require the URL format http://localhost:8080/[demo]/dist/ instead of http://localhost:8080/dist/.

If you have created a specific demo while setting up the project, you should replace [demo] in the URL with the appropriate demo name. For example, if you created a demo named "my-demo," the URL should be http://localhost:8080/my-demo/dist/.

It seems there might be a small misconfiguration. Please try running the following command in your terminal:

gulp localhost

After that, open your browser and navigate to http://localhost:8080. You should see a list of available themes. Click on the theme folder you are working on, and it should redirect you to the correct URL.

Let me know if this resolves the issue for you.