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