Shovel Knight: Treasure Trove

First off, I suggest going into options and switching your relic activation to Button mode so that you only have to tap to use relics rather than having to use the left thumbstick/d-pad and button combo. It makes the entire game much easier IMO.

This achievement is super simple. Just play through the Plains stage (the very first mission) and fight the Black Knight at the end any way you wish. When he gets down to half of a circle of health left, wait for him to fire one of his purplish-pink balls of flame at you and reflect it back at him with a swing of your shovel. The silly tin can doesn't even try to dodge it, so it will finish him off for the achievement. This could also be combined with any of the other achievements in the video that are done in the Plains mission, including No Damage, but IMO it's not worth risking ruining your No Damage run waiting around for him to fire at you and potentially missing your swing.

In the interest of creating as much of a one-stop-shop as possible, I've included 22 of the miscellaneous achievements in Shovel Knight in the video below. I wanted to include Knuckle Down as well, but the stage for that was already complete in my game and I haven't played back through again to unlock it. You can see a fight against the Black Knight polishing him off with a taste of his own medicine at the 03:37 mark.

this is done in the first level. the boss is the black knight and he will have three attacks.

the first attack is swinging his sword.

the second is him bouncing about after you with his sword down, like your bounce attack.

and the third is the projectile.

He will shoot at you after the bouncing, he did for me at least, and it is pretty obvious as he will look like he is winding up for a swing and a pink flash will form on his sword. the pink flash will then shoot out at you.

to reflect it, just swing at it when the projectile reaches you.

the shot will only take half a point of life off, so you will either need to hit him twice with it, or hit him enough times that he only needs one more hit.

rather simple.

*** EDIT***

It has been brought to my attention that there is a chance of this glitching for some players. Apparently the developers know of this issue and are working on a patch for it.

If it does glitch, then I am not sure how to get around it other than to wait for the patch.

Thank you Habfan5693 for the information