The gameplay is heavily based around tactics and equipment that real "Tac Teams" use, and features dozens of different weapons, 5 different unit classes, perks, and a leveling system.
Aside from dozens of self-contained missions, there are also several campaigns, which basically a series of single missions with a loose story connecting them, with casualties and deaths carrying over from one mission to the next.
A spinoff called Door Kickers: Action Squad was released in September 2018. Rather than turn based tactics, the game is instead a side scrolling real-time tactical shooter.
Door Kickers contains examples of the following tropes:
- Artificial Stupidity: Invoked in a realistic and rather satisfying way. Armed enemies tend to be divided into hiders (whom stay in a single room, often in a corner) and movers (who, once alerted, will try and move to attack your team, or alternatively start patrolling). Enemies seem to enjoy walking through the same door your SWAT team has their guns trained on, and they only rarely seem to take cover. This all ties into the fact that they're untrained and often just junkies with guns of varying type.
- Alliterative Name: Many of the enemies follow this trope. Examples include Tackdriver Tim, Operator Orville, Grenadier Glenn, Businesslike Ben, Juggernaut Jim, and Jacketed Jake.
- Boom, Headshot!: Officers are able to perform the Mozambique Drill when using a pistol at close range, where they will fire two quick shots and perform a headshot with the third. The headshot is a guaranteed kill that ignores any armor, which is extremely helpful in dealing with armored enemies who otherwise may require over a dozen bullets to kill.
- Cold Sniper:
- While the player will never actually see the sniper in person, his voice tone, while calm and professional, can be off-putting to some people.
- Parodied in the official web comic, where the officers assume this trope is in play, but the sniper is revealed to a obese man sitting comfortably in his chair and listening to music while surrounded by various types of junk food.
- Elite Mooks: While most of the game's enemies are outmatched in one-on-one combat even by low-level troopers with no perks and basic equipment, Mooks with assault rifles and body armor such as Operator Orville are a very different story.
- Luckily, My Shield Will Protect Me: Zig-Zagged, depending on the shield's coverage and how tough it is. It's possible for a big shield to protect a trooper from a hail of pistol fire, only for a few shots from a rifle to bring him down.
- One-Man Army: Mostly averted, but not impossible to invoke. Teamwork, timing, and effective use of equipment is crucial from the beginning, and trying to micro-manage a single trooper and play the game like a third-person shooter will often end in death. However, with Trooper training, perks, and raw player skill, it's possible to do a level with only one Trooper. There's even a challenge specifically rewarding you for it.
- Required Secondary Powers: In order to use their flashbang grenades most effectively, SWAT troopers have equipment and training that makes them immune.
- Revolvers Are Just Better: Averted. The revolvers available offer no real advantages over the .45 pistols, but have multiple weaknesses such as a lower fire rate, smaller ammo capacity, and inability to pull off the Mozambique Drill. The weakest enemy in the game also uses a .38 revolver that is ineffective in harming your officers.
- Samus Is a Girl: Downplayed. The names and facial features of several Troopers make it clear that they're female, but the game never makes a big deal of it, so its possible to have a successful Trooper without realizing they're women.
- Shown Their Work:
- Officers who use certain handguns (such as ones equipped with compensators) cannot use them alongside the Center Axis Relock perk, as the Center Axis Relock stance puts the handgun close to the user's face and could result in injury due to the compensator redirecting gases.
- The revolver toting enemy is named Junkie Harry
- The description for front-plate only armor includes the quote from Black Hawk Down of the ranger explaining to Grimes that he won't need his rear ballistic plate unless he plans on running away.
- The steam achievement for unlocking the assaulter class is named "Now I have a machinegun"