Here is the full list of all 33 Shovel Knight Showdown achievements.
As Shovel Knight, win the match with a reflected projectile.
As Plague Knight, defeat multiple foes by hurtling through them with a single Spin Burst.
As Specter Knight, use a Dash Slash to win by dunking a foe into lava or a pit that you would've fallen into.
As King Knight, reach the winning gem while still spinning after bashing into a foe.
As Shield Knight, use a single Shield Rush to both block a projectile and win the match.
As Black Knight, win the match by dodging a player and hitting them with a Dark Wave.
As Propeller Knight, defeat 2 or more foes without touching the ground.
As Mole Knight, absorb 10 hits while submerged in a single match.
As Treasure Knight, win the match by defeating a foe with a bouncing diamond that you popped.
As Polar Knight, defeat multiple foes with a single use of the Polar Plow.
As Tinker Knight, win the match by knocking an enemy into lava or a pit with the Definitely Intentional Trip.
As The Enchantress, remain in the air for 30 seconds without touching the ground.
As Baz, stun multiple foes using one use of Electrify, then hit them before they recover.
As Reize, win the match by Dive Kicking an enemy to propel yourself to the winning gem.
As Mr. Hat, get a KO with each of your 3 hats in a single match.
As Phantom Striker, use the Strike Step to reach the winning gem while donning the Phantom Shroud.
As Mona, win a match by knocking a charged hazardous potion at a foe.
As Dark Reize, defeat 3 foes as you exit your teleport in a single match.
As Goldarmor, win the match by down thrusting off of the Throwing Anchor to reach the winning gem.
As Liquid Samurai, win a match by collecting 3 gems without breaking your run stride.
Finish Story Mode without using a continue.
Attain a score of 100,000 in Targets.
Finish 10 matches in any stage with lava or a pit without falling in.
Use each of the items once.
Successfully parry 10 times during one match.
Fall through the warp floor 50 times.
Complete Story Mode on Hard difficulty.
Knock opponents into lava 50 times.
Defeat 50 Troupples during an encounter with the Troupple King.
KO 100 total opponents.
Win a stock match of 3 or more without losing a single stock.
Win Sudden Death 5 times.
See 20 different modes in Chester's Choice.