There is now a windows-beta-standalone channel where you can download Orlop as a regular exe file and start it from the itchio client :)

Hey, I just updated the project. You can now import assets via drag & drop and I added two buttons for it as well (next to the search bar and in the bundle detail inspector).

Hey, I just updated the Project - You should now be able to download via itch.io client, BUT currently it only downloads the .msi installer, with which you can install Orlop. Sorry, if that's inconvenient. I'll try to fix that in the next versions as well.

Admittedly, it can be a bit confusing currently. You have to create a bundle first and then via the "three dots"-menu of the bundle choose "Add Assets.
Drag and Drop will be added in the next version!
 

Good point, will do!