Here is the full list of all 84 StarBreak achievements.
Collected 10000 Boosts
Find The Bridge
Complete the Elite Underground Base
Complete the Frozen Blight
Complete the Elite Fungus Cave
Complete the Elite Frozen Blight
Achieve MK V with any shell
Wear all Custom equipment
Find Shu
Complete the Elite Vanquished
Find The Chronicle
Complete the Elite Strands
Complete the Graveyard
Find Thoth
Killed by Goldtooth
Find Ptah
Kill 20000 enemies
Complete 100 midbosses
Have 100 allies increase their MK
Buy vanity item
Complete the Temple of the Lost
Make a purchase at a Secret Shop
Find Horus
Achieve MK IV with any shell
Find Set
Complete the Strands
Find The Mother Crystal
Find Bes
Get 10 impressive performance callouts
Deal a million damage
Killed by spikes in the Fire Forest
Have 20 allies complete a new mission
Picked up Prototype
Complete the Elite Fire Forest
Find The Hidden Waterfall
Find The Sympathizers
Complete the Fungus Cave
Find The Holo-Statue
Complete the Underground Base
Complete mission with less than 10 hp
Open a chest as a Spark
Achieve MK III with any shell
Blocked 1000 Bullets
Complete the Vanquished
Killed by falling in Strands
Complete 20 midbosses
Killed by Fungus Cave boss mouth
Lost 100 allies
Kill 1000 enemies
Collected 100 Boosts
Register your account
Achieve MK II with any shell
Complete the Fire Forest
Destroy a Shell
Complete the Tutorial
Complete the Star Cathedral
Complete the Elite Graveyard
Complete the Elite Temple of the Lost
Complete all missions with a Wildfire
Complete all missions with a Duskwing
Complete all missions with an Ironclad
Complete all missions with a Fabricator
Get 100 impressive performance callouts
Achieve MK VI with any shell
Killed by Sweeper
Killed by Scavenger Tail
Killed by Stone Head
Wear all Experimental equipment
Wear all Prototype equipment
Blocked 100000 Bullets
Lost 10000 allies
Have 10000 allies increase their MK
Have 1000 allies complete a new mission
Reach Wave 50 in the Underground Base
Reach Wave 50 in the Elite Underground Base
Find The Embryo
Achieve A Rank with Wildfire
Achieve S Rank with Wildfire
Achieve A Rank with Duskwing
Achieve S Rank with Duskwing
Achieve A Rank with Ironclad
Achieve S Rank with Ironclad
Achieve A Rank with Fabricator
Achieve S Rank with Fabricator