This game is not like Witcher or Mass Effect. No big decisions to make here. Story and dialogues are just there to carry the gameplay and offer direct entertainment.
You also have to think about that the game is meant as a hop-in, hop-off co-op game. Deep decisions based on a system in which you can disagree with your buddy and the outcome depends on a rock, paper, scissors isn't a good design approach.
Just think about a situation in which you let a buddy play your second character for a while and he disagrees in a situation with you and wins the argument. You would have to live with the outcome of that decision for the rest of the game, even if you continue in single player mode.
So, yes, this game doesn't offer deep decisions.
