This achievement is easier than it sounds, with the right strategy.
Conditions- The boss needs to be defeated without being hit (not just without losing health). Meaning if you have bonuses like shields or extra health, as soon as that goes down, the achievement is void.
- The achievement is missable. You can only fight each boss once per playthrough. If you've already defeated it, you need to start a new game (or continue on into NG+ for a slightly tougher fight)
Preparations- Get the strongest
Sword & shield (and fully upgrade it to make the fight go faster).
- Get to the room before the boss room in the Tech dungeon and warp back home with the Merchant Emblem
- Quit to the main menu, and make a backup of your save in case something goes wrong
- Warp back to the boss room and get ready to fight
Boss breakdownThe fight is fairly safe with the sword and shield. Every phase can be handled pretty much the same way:
- Get in close, and give a good three swipes with the sword (there’s almost always time for at least three)
- Block with your shield. Every attack EXCEPT for when the orb turns pink can be blocked. If the orb turns pink, you’ll need to evade it five times until it rests, then you can get in close (the path it travels is telegraphed by a line of electricity).
- Wait for the attack to finish, then unload with the sword until it teleports.
- Repeat until defeated
A few tips for efficiency:
- If it unloads the area of effect attack, you can walk with your shield up until you’re in a safe zone and start wailing at it.
- If it does the spinning attack, you can get an attack in each spin, but there’s a chance you’ll get hit.
- In general, as long as you’re patient the fight is pretty safe, so there’s little need to optimize. The only “dangerous” attack is when it moves around.
The achievement pops as soon as the boss is defeated.
In case you get hit/die/defeat the boss after taking a hitJust immediately quit to the main menu and choose "continue". You should start off in bed before going into the warp. But in case something goes wrong, you have the backup save to restore from. Because you did make a backup, right?
Video of the above strategy:
Bug reported by Jalgrin:
I got the kill on the boss just as it teleported which bugged it out and froze me in place while the boss continued teleporting around. It also gave me the achievement for beating it but not the one for Perfecting it. I just quit and reloaded the game and made sure to not get the last hit in during a teleport and it popped the second time.