I think it was only the left and right buttons that would work to reverse directions, but yep, you could!

https://gaming.stackexchange.com/questions/19130/is-it-possible-to-use-the-second-controller-to-control-the-ducks-in-duckhunt

I actually really miss the basic gameplay mechanic of games like Exodus and Joshua. Not sure what it’s called, I guess quasi-platformer? You could walk freely in 2 dimensions, but it wasn’t a top-down view since there was still gravity. And it was side scrolling, but you could go left to right freely as well. Basically the levels were just puzzles with bad guys wandering around and you had to find the exit while avoiding getting stuck or killed.