Here is the full list of all 40 Rack and Slay achievements.
Collect a coin by defeating an enemy carrying it.
Defeat 30 Normy enemies.
Defeat 15 non-Normy enemies.
Survive 50 levels.
Win 5 Crawl mode runs.
Win 5 Delve mode runs.
Gain 100 gold.
Pick up 25 collectibles.
Re-roll items 20 times.
Open the credits.
Destroy an obstacle.
Buy a random item in the shop.
Have +20% shot power.
Have at least 10 max health.
Have at least 12 shots.
Find a link to the dev's previous game.
Defeat a regular boss enemy.
Beat the Picky Klutz challenge.
Win a daily run.
Win a wild run.
Defeat a Swordmaster boss enemy.
Defeat a Bomber boss enemy.
Defeat a Shooter boss enemy.
Defeat a Blinder boss enemy.
Defeat a Grenadier boss enemy.
Defeat a Brittle boss enemy.
Defeat a Trapper boss enemy.
Beat the Berserk challenge.
Beat the Big Spender challenge.
Beat the Explosives Expert challenge.
Beat the Dunken Master challenge.
Beat the Second Wind challenge.
Beat the Veteran Hunter challenge.
Beat the Bouncyland challenge.
Beat the Gang Leader challenge.
Beat the Spiky Gauntlet challenge.
Defeat an enemy by shooting a volatile spike into it.
Defeat an enemy by having it end its turn on a teleporter.
Have 20 items.
Defeat all enemies and pick up all collectibles in a level.