Hahaha well, I did it as well while testing, then decided to save the notebook keyboard and moved to use two gamepads, but the best part was just swap controller to use the second character (if still alive), when the first die. However usually it lasted only a few seconds.
Interesting though, it could be a proper game mechanic if done properly and with special designed levels.
Thanks for playing, by the way. How far did you went?