We've fixed the script to workaround Photoshop limitations when there are 500+ layers ("rasterize all" doesn't work!). Please grab the latest script (version 6.12) and it should work for you!
Using Photoshop CC 2017 it took 6 minutes and 15 seconds for the script to run, exporting 387 images. A colleague reported it taking longer with a newer version of Photoshop. That's a bit unfortunate but I doubt there is much we can do about it. 🙁
We also fixed the script for layers that have 0 opacity. Image files for those layers will not be written. If you want to hide layers but still have images written, you should use the visibility eye in Photoshop to hide them and uncheck Ignore hidden layers
on the script dialog.