If making this project again there are several things we might try differently:

• Design a uniform end return that would slow and redirect the coin cell at the end of each ramp.  The end return being used now is a bit of a hack
• Catch the coin at the bottom and have it do something instead of just roll out (e.g. light and hold the top LED)
• Look at adding a motorized coin cell return to the top of the tree
• Consider other features - like nails used similar to a Pachinko machine or a display to count trips

Credit to Adrian for the idea of a rolling coin cell.  In fact, credit to Adrian for all the real thinking....