The enemies in the inFamous: Second Son can be divided into four different groups. The first one are the standard D.U.P. soldiers, appearing in a few different "variants", with different armor and armament. Generally speaking, those enemies pose the lowest risk from all of the enemies described in this section, and you should be careful when dealing with them only if they are in a bigger group, which can begin a massive barrage and literally cover Delsin with grenades (effectively preventing escape and elimination of threats). While being in this situation, you should concentrate on individual foes, to successively reduce the numbers of enemy troops.
The second group are the enemies endowed with supernatural powers (an example is visible on the above screenshot). Like in the case of the standard soldiers, enemies in this group differ from each other, as they can wield different powers and use various types of firearms (a minigun or a rocket launcher, for instance). Regardless of the encountered enemy, you shouldn't underestimate him, for enemies in this group deal more damage, can move around faster (as well as run away from Delsin, if needed) and they are harder to kill (it could be necessary to get rid of the enemy's shield or to finish him off after dealing a substantial amount of damage).
The third group are the enemies using various means of transportation (for instance, an armored vehicle, like in the above screenshot). In the beginning of the game, you will encounter as much as an armored vehicle, but further into the game you will stumble upon tanks and / or helicopters. An effective way to deal with them is a priority, because in most cases they have huge firepower, and can bring you on the brink of death in seconds. Don't forget to use the proper power versus a certain threat, like a Cinder Missile to blow up the enemy vehicles.
The last, fourth group, are the bosses. They appear solely in defined, scripted places of the single player campaign and every encounter with a boss is unique. Detailed information about defeating each and every one of the bosses in the game can be found in the walkthrough part of the guide.