Combat is completely bloodless, which may seem odd for an ACW game. Disordered units suffer a variety of penalties, from lowered cohesion to the loss of most of their ZOCs. What this means is that the only ways to kill a unit are to either attack it while it's routed or to surround it. Despite this it is still possible for a reckless player to lose a lot of units. Return fire and counterattacks.
Counterattacks are possible if the attacker in a charge rolls a sufficiently bad number.
Of the two, return fire is by far the more useful adaptation. There hasn't been one counterattack in any of the games of Glory that I've played. Most Civil War battle games these days include some sort of method of preventing players' bloodthirstiness from driving losses to unrealistic levels. In Glory this is handled via an optional rule for Commitment. Each AM has a commitment range printed on it.