With the game knowledge that Bruno has, Bruno had no need for God's assistance, in order to know the basics of how to effectively kill an enemy. Even if he wasn't a gamer, he probably would've still known that it is better to use a gun than a fist, in a fight against monsters.
Or maybe not… Because, if he was in fact someone that didn't touch video games at all, he might have clumsily forgotten that he has a weapon in some kind of accessible subspace. It isn't common for a human to pull out something out of thin air, after all. Hence, Bruno would most likely have made such a clumsy mistake.
Luckily, Bruno isn't that kind of an ignorant fool, and knew exactly how to handle different kinds of situations with or without someone's help. He knew exactly how to time things right, and because of that, he knew exactly when to pull out his auto rifle to shoot the ugly looking lizard.
