At its core the game is rather simplistic. You play as a variety of characters fighting against each other on a variety of stages, all based on different LEGO Themes. You defeat other players by depleting their health bars or, if possible, knocking them off the stage. There are three modes: a capture the flag style mode where your team must capture and keep control of a central point, a free-for-all mode where you must get as many KOs as possible before time runs out, and a mode in which you must collect the most of a certain item. The last one is also split into free-for-all and team versions. A later update added "Free-For-Brawl" mode, a more traditional platform fighter mode where each character has three lives.
The main thing separating this game from other fighting games is, in true LEGO style, its focus on customization. Instead of having a fixed roster, the game allows you to put together your own "brawler" using parts you've unlocked through playing. Though you can unlock pre-existing characters from LEGO's many themes, they do not have any special abilities separating them from any characters you might create yourself.
Because all Brawlers share the same move set (a basic melee attack, a dash attack, and a ground pound), items play a key role in battle. As part of customization, you get to select a list of three items a Brawler can pick up from item boxes scattered around every stage. In addition, each stage has a set of unique items that can be found in its boxes along with a set of standard items that show up on all stages for all Brawlers.
The game currently has 12 themes: Alien Conquest, Castle, Hidden Side, Jurassic World, Monkie Kid, Ninjago, Ninjago Prime, Ninjago Seabound, Pirates, Space, Vidiyo, and Western.
LEGO Brawls contains examples of:
- Accidental Suicide: It's entirely possible to kill yourself by accidentally falling off the stage. Doing so will show a special animation of your Brawler looking embarrassed for doing so.
- Action Girl: Any female Brawler can kick just as much butt as the male ones. Possibly more if you're good enough at the game.
- Adaptational Badass: Characters that take non-combat roles in their home series such as the various Jurassic Park protagonists and generic civilians are now capable of fighting with the best of them.
- Adaptational Wimp: NRG Nya is quite a bit weaker than she was in Ninjago. She can be defeated by any old weapons and while she unlocks some of the best items in the game they only last a little while.
- Air-Dashing: You can preform your Dash Attack in midair.
- And Your Reward Is Clothes: The characters you unlock don't necessarily do anything special and function more as alternate outfits than anything. You can even mix and match them.
- Attack Reflector: The Hero's Chalice item reflects projectile attacks.
- Battle Intro: Depending on your weapon, your Brawler will have a different intro animation.
- Capture the Flag: One of the three game modes (and by far the game mode with the most stages) is a team based mode where the main objective is to capture a central area.
- Character Customization: One of the game's main focuses is the creation of your own custom Brawler using parts you unlock through playing the game.
- Dash Attack: Every Brawler has a dash attack as does the mech on the Ninjago stage and certain items.
- Death Is a Slap on the Wrist: Since the main objective of most game modes isn't to defeat your opponents (and for the ones where it is winning is based on kills not who you beat), characters can respawn infinitely just like any other LEGO Game. Averted in the Free-For-Brawl mode, where characters only have three lives.
- Ground Pound: All Brawlers have a ground pound attack.
- Improbable Weapon User: Your Brawler can use a wide variety of weapons from the mundane (a sword) to the unusual but feasible (a pitchfork) to the just plain absurd (a literal baguette).
- Instant Awesome: Just Add Mecha!: If you get to the center of the standard Ninjago stage first you get to pilot a mech.
- Invincibility Power-Up: The game has multiple invincibility power ups such as the Pizza costume, which both makes you invincible and causes you to project a healing field that heals your allies but at the cost of being unable to attack, and the Hero's Chalice, which does allow you to attack. Neither of these make you immune to knock back.
- Jump Jet Pack: The Blacktron Stage Exclusive Jetpack power up allows you to gain an extra high jump when activated.
- Knockback: Being hit by any attack will knock you backwards.
- Laser Sword: Several of the Space weapons count as laser swords though only one is named such.
- Mascot Fighter: While the game encourages you to create your own Brawler it contains many pre-existing characters from the various LEGO Themes that you can use in battle.
- Platform Fighter: The game's stages features many platformer elements though only some of them allow the player to be knocked off screen.
- Player Versus Player: The game is exclusively PvP.
- Ring Out: It's possible to die from falling off some stages (or falling in water and getting eaten by sharks in the Pirate stage).
- Threatening Shark: If you fall in the water on the Pirate stage you get eaten by a Shark, with the shark even having its own victory animation. There's also a shark ride as part of that stage's unique set of items.
- Tornado Move: It's possible to unlock the ability to use Spinjitzu as an item.
- Victory Pose: There are a number of victory animations you can give to your Brawler.
