Hmm...I tried this out for myself—I collected all five spheres, returned to the dark area where you first come in, closed the app, then launched the game again and I couldn't move. Actually, even collecting one sphere, or two or three, etc., then returning to the beginning dark area and then closing the app will cause this to happen. I'll let the developers know that this is an issue.
[Edit: Got an e-mail response from Amanita today—May 7th—saying that they are going to release a fix for this issue very soon.]
In the meantime, the only thing you can do is to start that part over again from a save. If you're unsure how to do this: Tap on the star in the upper left-hand corner, then tap on the little nest icon with the arrow:
Choose the farthest right screen from the ones at the bottom there—Part 9. Tap the middle of the screen and then tap the checkmark to load the save. Just make sure not to close the app if you're in that dark area.
