Here is the full list of all 221 Army of Ruin achievements.
Shrine II - Ruin 1 - Complete the Stage with Onyx Coin
Shrine II - Complete the Stage with Rotting Coil,Poison Root,Elven Bow
Upgrade Jade Wand to Level 5
Shrine III - Complete the Stage without infusing any Earth
Shrine III - Complete the Stage
Forest Stage ∞ - Reach Minute 30
Upgrade Brittle Stone to Level 5
Graveyard Stage ∞ - Reach Minute 30
Reach Experience Level 40 with Abaddon
Upgrade Sphere of Destruction to Level 5
Glacier Stage II - Ruin 3 - Earn 5,000 Coins with Neptune
Upgrade Ghostly Trail to Level 5
Upgrade Caltrops to Level 5
Forge Stage III - Ruin 2 - Complete the Stage with Mork, and infuse Fire Fire Fire
Glacier Stage III - Ruin 3 - Pick 3 Charms with Kroat
Shrine I - Complete the Stage
Shrine I - Complete the Stage without moving
Graveyard I - Complete the Stage without moving
Upgrade Dark Staff to Level 5
Upgrade Pirate Anchor to Level 5
Reach Experience Level 25 with Kroat
Upgrade Ink Geyser to Level 5
Reach Experience Level 40 with Experiment XIX
Upgrade Sparksword to Level 5
Graveyard Stage III - Ruin 2 - Defeat all special bosses with Experiment XIX
Upgrade Swift Tornado to Level 5
Shrine II - Ruin 2 - Defeat all special bosses with Samael
Glacier Stage III - Complete the Stage without infusing any Earth
Unlock 150 items (Characters, Equipment and Features)
Reach Experience Level 40 with Samael
Upgrade Fire Wings to Level 5
Reach Experience Level 30 with Michi
Upgrade Throwing Bombs to Level 5
Shrine II - Complete the Stage
Glacier Stage I - Ruin 3 - Evolve 3 weapons with Kyros
Reach Experience Level 25 with Kyros
Glacier Stage II - Ruin 2 - Complete the Stage with Tisha and Explosive Flask,Seal of Purity
Glacier Stage I - Ruin 2 - Complete the Stage with Selina, without infusing any Darkness
Glacier Stage I - Ruin 1 - Complete the Stage with Obsidian Crown
Forest Stage III - Ruin 3 - Reach Experience Level 40 with Tisha
Reach Experience Level 25 with Tisha
Pick 3 Charms
Glacier Stage III - Complete the Stage
Glacier Stage II - Complete the Stage with War Drums
Evolve 4 weapons
Glacier Stage II - Evolve Necromancer Gauntlets
Glacier Stage II - Complete the Stage
Glacier Stage I - Upgrade Toxic Stench to Level 5
Earn 30 Stars
Pick 1 Charms
Glacier Stage I - Reach Experience Level 25 with Ogol
Earn 21 Stars
Unlock 60 pieces of equipment (Weapons and Trinkets)
Earn 20 Stars
Earn 16 Stars
Glacier Stage I - Complete the Stage
Earn 17 Stars
Unlock 50 items (Characters, Equipment and Features)
Unlock 100 items (Characters, Equipment and Features)
Win a total of 6 stages
Graveyard Stage III - Complete the Stage
Graveyard Stage II - Ruin 2 - Defeat all special bosses with Ker
Graveyard Stage I - Upgrade Crawling Root to Level 4
Forge Stage II - Ruin 1 - Defeat all special bosses with Ogol
Forest Stage II - Upgrade Armor of Thorns to Level 5
Forest Stage III - Ruin 2 - Defeat all special bosses with Bhask
Forge Stage I - Earn 750 Coins
Forest Stage III - Ruin 1 - Defeat all special bosses with Lanyz
Graveyard Stage II - Ruin 1 - Defeat all special bosses with Ariana
Forest Stage I - Ruin 1 - Defeat all special bosses with Saul
Earn 8 Stars
Earn 20,000 Coins through all stages
Die a total of 5 times
Earn 15 Stars
Earn 12 Stars
Earn 5,000 Coins through all stages
Earn 18 Stars
Earn 2 Stars
Earn 5 Stars
Graveyard Stage I - Reach Experience Level 20 with Ariana
Forest Stage III - Upgrade Ranger Bow to Level 5
Earn 10 Stars
Use the Bomb Power 10 times through all stages
Forge Stage III - Upgrade Leather Bracer to Level 5
Earn 500 Coins
Reach Experience Level 25
Forge Stage II - Reach Experience Level 30 with Ogol
Defeat 100 bosses through all stages
Die a total of 10 times
Forge Stage I - Ruin 2 - Complete the Stage with Ice Mirror
Graveyard Stage II - Complete the Stage with Magic Staff
Use the Freeze Power 10 times through all stages
Graveyard Stage I - Ruin 2 - Complete the Stage with Whirlwind Pickaxe
Open 5 Chests
Earn 30,000 Coins through all stages
Forest Stage II - Complete the Stage with Energy Bolt
Forge Stage I - Upgrade Magnifier to Level 5
Graveyard Stage II - Upgrade Travel Boots to Level 5
Kill 3000 enemies
Forest Stage II - Ruin 2 - Complete the Stage with Buckler
Use the Haste Power 10 times through all stages
Forest Stage I - Upgrade Volcanic Orbs to Level 5
Forge Stage II - Reach Experience Level 30 with Saul
Use your skill 15 times
Use your skill 200 times through all stages
Upgrade Dragon Heart to Level 5
Forest Stage II - Complete the Stage
Graveyard Stage III - Complete the Stage with Storm Javelin
Graveyard Stage I - Complete the Stage
Upgrade Throwing Axe to Level 5
Reach Experience Level 15 with Ker
Upgrade Ranger Bow to Level 5
Forge Stage III - Complete the Stage
Upgrade Ancestral Razor to Level 5
Forest Stage III - Complete the Stage
Upgrade Magical Slingshot to Level 5
Upgrade Marksman's Crossbow to Level 5
Upgrade Golden Trident to Level 5
Reach Experience Level 15 with Lanyz
Upgrade Spectral Dagger to Level 5
Graveyard Stage III - Ruin 1 - Complete the Stage with Ker
Upgrade Promethean Flames to Level 5
Forge Stage I - Ruin 1 - Complete the Stage with Lanyz
Upgrade Silvan Shell to Level 5
Forest Stage III - Complete the Stage with Meteorite Blast
Upgrade Jellyfish Ashes to Level 5
Forest Stage II - Ruin 1 - Complete the Stage with Bhask
Upgrade Battle Cog to Level 5
Upgrade Fire Staff to Level 5
Reach Experience Level 25 with Mork
Upgrade Mighty Punch to Level 5
Graveyard Stage III - Reach Experience Level 30 with Ker
Upgrade Frozen Shard to Level 5
Forge Stage I - Complete the Stage
Upgrade Toxic Stench to Level 5
Upgrade Ominous Gale to Level 5
Reach Experience Level 15 with Ogol
Upgrade Wolf's Fang to Level 5
Upgrade Storm Javelin to Level 5
Graveyard Stage II - Complete the Stage
Upgrade Meteorite Blast to Level 5
Upgrade Cupid's Arrow to Level 5
Reach Experience Level 15 with Saul
Upgrade Magic Staff to Level 5
Forge Stage II - Complete the Stage
Upgrade Homemade Explosives to Level 5
Upgrade Volcanic Orbs to Level 5
Graveyard Stage I - Ruin 1 - Complete the Stage with Viking Helm
Upgrade Flintlock Pistols to Level 5
Upgrade Crawling Root to Level 5
Forge Stage III - Upgrade Golden Trident to Level 5
Upgrade Landslide to Level 5
Forest Stage I - Complete the Stage
Upgrade Energy Bolt to Level 5
Reach Experience Level 15 with Ariana
Upgrade Quicksilver Spears to Level 5
Forest Stage I - Complete the Stage with Throwing Axe
Upgrade Whirlwind Pickaxe to Level 5
Reach Experience Level 15 with Bhask
Upgrade Blaze to Level 5
Upgrade Necromancer Gauntlets to Level 5
Graveyard Stage III - Ruin 3 - Defeat all special bosses with Obsidian Crown
Forest Stage II - Ruin 3 - Earn 4,000 Coins with Saul
Forge Stage II - Ruin 3 - Upgrade Panacea to Level 5
Forest Stage I - Ruin 3 - Complete the Stage with Voodoo Doll
Forge Stage I - Ruin 3 - Complete the Stage with Pirate Anchor
Graveyard Stage I - Ruin 3 - Reach Experience Level 30 with Lanyz
Graveyard Stage II - Ruin 3 - Kill 7500 enemies
Forge Stage III - Ruin 3 - Complete the Stage with Toxic Stench
Forge Stage II - Ruin 2 - Complete the Stage with Jellyfish Ashes
Glacier Stage III - Earn 4,000 Coins with Homemade Explosives
Glacier Stage III - Ruin 1 - Complete the Stage with Frozen Shard
Glacier Stage III - Ruin 2 - Reach Experience Level 35 with Bhask
Reach Experience Level 30 with Diana
Upgrade Bronze Starfish to Level 5
Reach Experience Level 25 with Tabia
Reach Experience Level 30 with Nekros
Glacier Stage II - Ruin 1 - Complete the Stage with Supply Crate
Forge Stage III - Ruin 1 - Complete the Stage with Ancestral Razor
Upgrade Wanderer's Lantern to Level 5
Reach Experience Level 30 with Traxx
Upgrade Chain Shot to Level 5
Forge Stage ∞ - Reach Minute 30
Reach Experience Level 40 with Neptune
Glacier Stage ∞ - Reach Minute 30
Reach Experience Level 40 with Midas
Upgrade Living Paintbrush to Level 5
Upgrade Pirate Cutlass to Level 5
Unlock 200 items (Characters, Equipment and Features)
Shrine III - Ruin 3 - Evolve 3 weapons with Abaddon
Shrine III - Complete the Stage infusing Wind Wind Wind
Shrine I - Upgrade Wolf's Fang to Level 5
Shrine III - Ruin 1 - Complete the Stage with Magic Needle
Upgrade Unfulfilled Promises to Level 5
Reach Experience Level 40 with Azazel
Upgrade Chain Lightning to Level 5
Shrine I - Ruin 1 - Complete the Stage with Devilish Eye
Upgrade Lapis Sword to Level 5
Upgrade Divine Top to Level 5
Shrine I - Upgrade Ice Tear to Level 5
Upgrade Mystical Firecrackers to Level 5
Shrine ∞ - Reach Minute 30
Upgrade Anvil of Heaven to Level 5
Shrine II - Complete the Stage infusing Ice Ice Ice
Upgrade Magatama to Level 5
Upgrade Fiendish Tear to Level 5
Glacier I - Complete the Stage without taking any damage
Glacier II - Complete the Stage without moving
Forest III - Complete the Stage without taking any damage
Forge III - Complete the Stage without opening any chest
Graveyard II - Complete the Stage without taking any damage
Forge II - Complete the Stage with 22:00 minutes or more on the clock
Graveyard III - Complete the Stage spending 20,000 or less in Upgrades
Forest II - Complete the Stage spending 5,000 or less in Upgrades
Glacier III - Complete the Stage with no Capacity Upgrades
Forge I - Complete the Stage without purchasing any Upgrade
Forest I - Complete the Stage with 16:00 minutes or more on the clock
Shrine III - Complete the Stage with 28:00 minutes or more on the clock
Upgrade Command Baton to Level 5
Shrine II - Complete the Stage without opening any chest
Upgrade Hitman Goggles to Level 5