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