Here is the full list of all 67 Incursion The Thing achievements.
Stop 100 enemies
Advance 10 waves early.
Complete a level with the highest rating.
Advance 5 waves early.
Stop 500 enemies.
Complete 5 levels with the highest rating.
Train 5 healers.
Train 20 units with splash damage.
Kill Petyan Gaz.
Train 100 basic units.
Cast 10 spells.
Cast 30 spells.
Complete the 29 main levels.
Complete the 29 main levels on the highest rating.
Train 15 ninjas.
Train 20 eleven archers.
Reach Targa's level.
Get 3 gems on the Gorge Bridge stage without recruiting archers and wizards.
Get 3 gems on the Encounter stage using only hero forces.
Get RED unlocked.
Defeat Ettyr.
Defeat Xyllos, the last shadow demon.
Defeat the Great Ice Elemental, one of the keepers of the rune.
Defeat Rooltuk, the underground king.
Defeat Pharon'Ahn in the first battle.
Defeat Pharon'Ahn.
Complete the Trap stage without any Ent death.
Prevent Petyan Gaz from ressurecting on the Tomb of Petyn Gaz stage.
Kill 2,000 enemies.
Kill 5,000 enemies.
Get Targa to level 10.
Get RED to level 10.
Get 20 gems.
Get 50 gems.
Change the location of your warriors 300 times.
Let your troops be reborn 200 times.
Get the Machine Gun unlocked.
Kill the Broodmother, the cave defender.
Hire the Potbellied Demon on the Dragon Cave stage.
Complete the Artifact level without losing a sage.
Let the Worm eat your troops on the Worm Valley stage.
Complete the Worm Valley stage without losing any warriors to the Worm.
Let the Worm eat 20 units of your army on the Habitat of Troll stage.
Complete the Habitat of Troll stage without losing any warriors to the Troll.
Keep the gates undestroyed on the Sarensland Gates stage.
Survive until reinforcements arrive on the Sarensland Gates stage.
Defeat The Thing, the leader of darkness.
Get the Pet in your order.
Get the Flying Pet in your order.
Jump 100 times using the Teleportation Sphere.
Cast the Targa Storm spell 4 times.
Let RED exchange souls with other units 40 times.
Use the Necromancer to raise 100 skeletons.
Get 100 enemies Hexed by Puppet Master.
Possess Bychara using Puppet's Creep Control.
Use Ginny Gun of Wishes 30 times.
Cast the spell Freeze the World.
Let Twoface create 200 illusions.
Let 50 Lightning Beasts be summoned by Archmages.
Let Blademasters cause 100 Critical Strikes.
Bash 100 enemies with Doomhammers.
Complete any stage using all barracks.
Let the Tentacle eat any Hero on a Dried-up Lake stage.
Kill 50 Poisonous Worms.
Level up any hero to level 15.
Level up any hero to max level.
Complete the Trap stage without any hero dieing.