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