The first couple of times I fought him were an absolute disaster. At one point, I literally went across the entire underworld and still didn’t beat him.
I found this strategy that works almost flawlessly for Master Mode Wall of Flesh, and will work even better for Expert Mode and Classic Mode. I'll start out this guide by showing you everything you need to be the victor.
Necessary Gear
The first thing you’re going to need is Molten Armor. His lasers do so much damage to you that you’re going to need as much defense as you can get. Necro Armor is a decent option too, but you may find it more difficult to use because of its lower defense.
The next thing you’ll need is a Phoenix Blaster. This is crafted using Hellstone bars and a handgun found in the dungeon. If you’re having trouble beating Skeletron, I recommend checking out my guide on how to beat him on Master Mode. Once you get the Phoenix Blaster, craft a couple thousand Meteor Shot to use in the fight.
One of the most important items you need in this fight is an Inferno Potion. The reason you need this is because it surrounds you with a circle of fire that will destroy the Wall of Flesh’s leeches. Those annoying leeches do a ton of damage as well, and you won’t have to worry about them with this potion.
Boss Arena
So now that you have all of your items, you absolutely need to make a bridge in the underworld. It’s really not fun and kind of boring to do, but it almost guarantees that you’ll beat him.
I built my bridge to be half the length of my medium-sized world, but it turns out that it only needed to be about 1/3 the size of the world. For a small world, the bridge should probably be half the size of the world, and a large world should have a bridge at least 1/4 the size
When you're building the bridge, try to make sure that it's completely straight and that you dig through and remove any obstacles. You need to be able to dodge when necessary, and having blocks overhead can cause you do mess up and die.
Boss Strategy
Right before I started the fight, I consumed an Iron Skin potion, an Inferno Potion, and a random hot dog I found which increases health regeneration. When you throw the doll into the lava, make sure you face the direction you want him to come from.
As soon as he spawns, immediately start running away and firing the Phoenix Blaster. It’s best to stay just out of range of the Hungry, but far enough away to dodge the lasers.
Some lasers can be dodge by jumping straight up, and others will miss you if you run fast enough. The Inferno Potion will do most of the work of taking out the Leeches, but you might have to jump over them if they come towards you.
The key is to never stop moving and to keep shooting at his eyes and mouth. Use health potions whenever you need to, but try your best not to get hit.
Towards the end of the fight, he goes insanely fast and can kill you very quickly, so you just need to keep moving as fast as you can. Soon enough, you’ll beat the Wall of Flesh and your world will enter Hardmode.
