Practicing in challenging situations for that shot on an elusive big buck is always a great idea, although I doubt that many hunters will attach a zipline to their tree stand so they can swoop down like an eagle for a closer shot. Nonetheless, this video is very entertaining and will certainly expand your imagination for future practice sessions.
A slightly less dramatic practice method is to hang a plastic coffee can lid in front of a target backstop and let the wind direct the angles and movement. Sometimes the lid swings back and forth, but it mostly rotates so that you must wait for exactly the right moment to release. All you need is a piece of string and a plastic lid, and this low-tech tactic will teach you patience at the moment of truth.
Now, check out this fun and clever use of a zipline.