Thanks for givin' it a shot!
It's definitely not communicated effectively (we ran out of time to have a proper tutorial), but in order to have the copy hold the button down you will need to stand on the button for a few seconds, then start rewinding. You "cease to exist" in that location when you rewind and the copies are a replay of your past actions, so rewinding as soon as the button is pressed will make your copy "disappear" as soon as it reaches the button. If you did stand on and hold the button down for a bit before rewinding and the copy still disappeared right away, then that is a bug!
We're also exploring additional options for rewinding, such as spending X amount of rewind time to leave a copy that will stay in place for X seconds. The rewind to start was also implemented as a quick solution for player death. A solution going forward will be to have the player rewind from time of death if there is still rewind time available to use.
Raujinn, Drauc, and Mihai did a phenomenal job with the art and music, I'm glad to hear they stood out! The cutscene audio volume can use rebalancing though. Thanks again for the feedback!