It pops up randomly during the week, and no longer on weekends. Used to start Fri nights through Sunday. Don't like that it's random now. I play more often on weekends.
Don't like the energy rather than lives: two chances rather than five, so it makes it more difficult to attempt to get through to level five.
Levels that I previously had no issue getting through, very basic levels, now seem to have been engineered to make it almost impossible to pass and become increasingly more difficult the higher level you attempt.
All in all, this very enjoyable feature has now become a huge source of frustration. I no longer have fun playing it.