Thanks for the feedback!
Yeah i can imagine that the 20 seconds start to feel annoyingly long if you didnt know how to rewind manually. I share the sentiment of it needing more levels, i am currently working on it and intend to release it when ready. Another thing that is already implemented that you may also appreciate is that the rewind time speeds up gradually so that even that doesnt take as long.
Hope to see your feedback again on any of the updates :)