Here is the full list of all 16 Amaranthine achievements.
Kill 10 enemies in 1 secon
Reach 20 level on legend mode
Sell 100 weapons
Complete subwarp level
Ram 50 enemies
Complete game on legend mode
Destroy 5000 enemies
Complete game on normal
Destroy 12 cargo ships in a single run
Destroy the bomb
Destroy 1000 enemies
Complete level without taking any damage
Destroy the battlecruiser
Destroy the overwatcher
Destroy 250 enemies
Find legendary weapon