Credit to https://scratch.mit.edu/discuss/topic/2793/?page=14#post-6822800 for the workaround shown here. Keyboard controls: Press space or the right arrow key to go to the next slide. Press the left arrow key to go to the previous slide. Mobile controls: Click the arrows at the bottom to change slides.
1. You can have a backpackable version of this script by going here: https://scratch.mit.edu/projects/795499122/ 2. This works in Scratch 2.0 and 3.0, just not 1.x. 3. If it shows up as a blank backdrop for you, that's one of the slides. 4. There should be 4 steps (originally 3). 5. This is case sensitive, you have to make it all lowercased or it will not work (costume names are case sensitive) 6. You don't have to do this for backdrops: https://scratch.mit.edu/projects/918894112/