The Enforcer is a slow but powerful character. Batting away enemies with Shield Slam guarantees you will keep enemies at a safe range. Make sure to use Protect and Serve against walls to prevent enemies from flanking you.
The Enforcer's main means of dealing damage is through Riot Shotgun. While the attack is slow, it is also a ranged attack that can strike several enemies at once. This makes items that trigger on strike quite effective in the Enforcer's arsenal. Increasing the enforcer's rate of fire via Soldier's Syringe is also quite effective. Somewhat appropriately, the Prison Shackles are one of the Enforcer's best items; the ability to slow down enemies using the shotgun is crucial for crowd control.
It should be noted that the Enforcers Riot Shotgun has more impact than the Commando's Double Tap. The Riot Shotgun being able to knock back a greater variety of enemies when compared to Double Tap. For example; Riot Shotgun can knock away the colored Lemurians and the Wisps whereas Double Tap cannot.
Positioning for Shield Slam is crucial to success. Being the most stationary character, items that are most effective on the Enforcer are ones that help you take out large hordes of enemies at a time. The Will-o'-the-wisp, Brilliant Behemoth, Gasoline, and other "damage on-kill" items will help you build momentum and make short work of the waves.
Shield Slam will knock enemies, regardless of their orientation, towards the direction the Enforcer is facing. The hitbox for Shield Slam also extends slightly behind the Enforcer as well; however, hitting an enemy at the edge of Shield Slam's range if they are behind the Enforcer will send them backwards.
Protect and Serve can kill you just as easily as it could save your life. It is important to stagger your Shield Slam and Crowd Control abilities if you get into a bind.
Be careful of enemies like the Rock Golems or Sand Crabs, you want them close to block damage with your shield, but if they get too close, their long reach can still hit you for devastating damage, even from the front.
Mushrums are a particularly lethal enemy for the Enforcer: They have a damage over time, area of effect attack, that hits through Protect and Serve. Staying in the attack's effect can kill the enforcer in a matter of seconds. Evasive maneuvers must be taken against this attack.
Similarly, the player should keep an eye out for elite enemies. Those that are electrically charged or leave fire tracks (including Elder Lemurian's flame blast) will hit through Protect and Serve. As for elites that fire rockets (or nematocysts from Wandering Vagrant), these have a tendency to fly around and strike the enforcer in its vulnerable back. Backing up as the projectile fires will typically cause it to impact the shield because their targeting lock-on occurs at the start of flight.
The Spite artifact's explosions can also be very dangerous without enough move speed modifiers to make sure none detonate behind you.
(untested) Providence's ground shockwave and delayed explosion should be blocked if they impact the shield.
Cremator's projectiles will be blocked if they are in-flight and hit from the front. The impact explosion will damage if the white indicator is behind the Enforcer.