Before being deformed by the Culture Fluid, Bio-Broly in his base and Legendary Super Saiyan forms appeared identical to Broly in Broly - Second Coming, though without Broly's articles of clothing.
As Bio-Broly is a clone, he lacked Broly's battle experience and thus fights based on instinct.
Soon after awakening, Bio-Broly's power shattered the tank from which he was created, spilling the culture fluid.
This is especially evident when Krillin was actually able to put up a decent fight against Bio-Broly, and he was able to be harmed by Super Saiyans Goten and Trunks, whereas the real Broly managed to knock Krillin out in one strike before he could even move in to attack, and was unharmed by any of Goten and Trunks' attacks even while only in his normal Super Saiyan form.
Despite lacking these features, the clone managed to retain Broly's recklessness, lack of compassion and apparent invulnerability to attacks.
The Culture Fluid also makes Bio-Broly's body malleable, but greatly weakens him compared to his non-Culture Fluid covered Legendary Super Saiyan form.