Ours didn't go backwards.
You could play at the crank and kind of make it do funny things like, still not the DJ tool, but it was made to wind up and then it would stay at speed, while unwinding, for a while.
In one direction you could use crank "impulses" over time to result motor speed variation over time, work out some dampening in firmware.
How would you accommodate abrupt changes from one direction to the other?