Hitboxes are a feature in almost every game, however, they are typically standardized "boxes". Brawlhalla's hitboxes are actually circles that are within the weapon of each character. Note: Hitboxes are different from Hurtboxes. Hitboxes show where a player can be hit from with an attack, while Hurtboxes show where you (the attacker) can get hit from.
Each character will typically have hitboxes in the animation of their weapon to easily distinguish where they will hit from.
Here we can see that the punch from Kor has multiple colors. These colors are only there to make them easier to distinguish frame-by-frame. You can see the hitboxes of the punch. The yellow circle is the Hurtbox where Kor can be hit from. The Hurtbox is typically the same for every character.
Custom Weapon Hitboxes
Each weapon's heavy attack has a unique hitbox as you saw from the pictures above.
Here are just a few of those!
Hattori - Heavy Air
Lucien - Heavy Right
More to come soon!