I had been told there are ladders, but they're stairs. There is little fear-factor because you can't really 'see down,' so you don't have the feeling that you're suspended in air, and because there are railings for you to hold on to.
The series of steps can be daunting only because they are narrow. It would be no different than slipping down the steps in your house, Lord forbid. If you so happen to fall, you're not going to go tumbling into outer space or down a clif,f because you are tightly surrounded by the walls of the canyon.
In all, there are probably five or six sets, some of them with say 20 steps, and others with four or five. There's one main difference between the Upper and Lower Antelope Slot canyons that may help you decide which to choose if you care to do only one : The lower has a series of steps that you take in order to get to the very bottom.