Some things I kept in mind when designing Brawl is that he is in several iterations: loud, violent, volatile, a warrior, a combaticon, a tank... literally, angry. The vehicle I chose for Brawl was quite simply a dark green tank with traces of dark brownish gray with a light green Decepticon insignia on the left side of the glacis plate. The tank is armed with two additional missile cannons on the sides of the main central turret and gun. The extra firepower was inspired by his vavers counterparts similar modifications. 

When it came to his color, I chose the plain dark green in reference to his G1 color, but slightly altered to have the color of those green army men toys. And the dark brownish gray colors are in reference to the color you would find in a camo palette. When it came to Brawl's body, I wanted him, even in his robot mode, to look like a tank. I wanted him to be big. I wanted him to be huge! A body large and sturdy enough to withstand heavy incoming artillery... all coming at once. I wanted all the tanks front plating and the front lights to form the torso in a similar formation to that of the belly of a turtle shell known as the plaston. I had the treads take up the shoulders and upper arms. The turret and the main gun would end up on his back. All of these choices were based on the placement of his vehicle parts on his G1 counterpart. Also, the two side missile launchers would become dual handheld missile launchers. 

When it came to his head, I wanted Brawl's head to look similar to the masks found on several menacing space soldiers found throughout media, such as Stormtroopers from Star Wars and Ultramarines from Warhammer 40k, including the iconic feature of vents on the space around the mouth and the formation of the helmet structure. The structure of the helmet on the forehead was inspired by John Carver's helmet design from Dead Space 3 and the visor was inspired by Brawl's G1 visor, but thinner and contains red and yellow lights. The color of the mouth vents came from Brawl's G1 face mask, which was reddish pink. And I made it so that it glows whenever he speaks or makes vocal noises.