It looks smooth and runs fine.
I'm only facing problems with dowloading large photoalbums. Because the times it needs to zip the files and make it a downloadable it can look like nothing happens when clicking the download button. Unpatient people are clicking the download button a couple more times and the file will be downloaded multiple times.
I enabled the disabled the custom code but that didnt solve te problem.
Code
// download_dir cache direct access to zip / better caching and no need to access PHP / only works when download_dir_cache === 'dir'