Your first real boss fight with Nemesis will be at the Demolition Site. Shortly after trying to escape the walkway and fire that this beast is creating, you will find yourself on a small rooftop and this is where the battle begins..
Nemesis will be carrying around a Flamethrower and thus for this fight you want to try and avoid being turned to a burnt Jill Sandwich.
Nemesis will set the nearby obstructions on fire as well as the floor, though he will only burn the floor occasionally.
Also, if the floor does end up on fire it only lasts a short while, so try and avoid it.
What you want to do here in order to survive is to hide behind these obstructions and wait until you hear a click of him needing to reload his Flamethrower, this is your golden opportunity to deal damage to him.
Simply run around the back of him and shoot the Flame Canister on his back, I ended up defeating him with a simple Handgun. He really is no big deal during this fight, I didn’t even take any damage.
Anyway keep shooting at the Canister on his back and eventually it will explode. At this point he will begin to torch the floor and walk a much faster pace towards you.
Don’t get overwhelmed by him and simply lure him over to the Electrical Box, when he is close enough shoot the box and electrocute him.
He will stay stunned for a while and at this point you just want to finish him off.
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