Boiler Knight is the mini-boss of the Smeltworks, a hulking knight encased in a boiler suit. His attacks are slow but powerful. Boiler Knight will primarily charge across the screen, attempting to ram you. He also has an attack where he releases a burst of steam, pushing you back and dealing damage if you're too close. His most dangerous attack involves launching explosive projectiles that leave behind lingering fire. The key to damaging Boiler Knight is to attack his exposed back after he charges past you, or to use a Shovel Drop on his head when he's vulnerable. He is heavily armored from the front. After taking damage, he may become enraged, increasing his movement speed and attack frequency. Relics that allow for quick repositioning, like the Propeller Dagger, or those that deal area-of-effect damage, such as the Chaos Orb, can be very effective. Focus on dodging his charges and steam bursts, then counter-attacking his weak points.
