@Kiori - Here are some answers for you (hopefully) -You can use bundles along with the sprite packer atlases, but there is a specific workflow. First, even though your HD and SD sprites have the same name and general structure, they need to have two separate sprite sheets (you can't put them on the same one). Then, when building your bundles, there is an option to pack only the atlas and not the original sprite. I'm going off of the top of my head, but I believe it is "CollectDependencies". I will have to check when I get a moment (my own personal project is structured this way and I just haven't checked tro make sure the atlassing works yet). -This system works perfectly for all platforms. It is a simple matter of structure and I believe the demo was made for simplicity, so it only highlights one platform. Basically, you can build the bundles for all target platforms (you can even build them all at once) and then just have the device look in the correct folder using some platform defines. -The asset bundle name and variant drop downs in the editor work great (it's how I make bundles) and is definitely feature ready. -Regarding the pixels to units for SD versus HD: I have only tested my solution for UI's, but I did not have to change anything for SD and HD to work correctly (I really need to find the time to finish this project and get it out). Hope that helps Cheers.