Complete the indicated task to unlock the achievement.

Achievement	How to unlock
ASCII Centipede	Defeat first boss.
Collect 'Em All!	Collect Every Unique Gemstone.
Fifthteen Creature Kill Streak	Kill Fifthteen Creatures without getting hurt.
Finale	Defeat fifth boss.
Five Creature Kill Streak	Kill Five Creatures without getting hurt.
Gemstone Collector	Collect 50 Unique Gemstones
Gemstone Hoarder	Collect 100 Unique Gemstones
Great Tarantula	Defeat second boss.
Massive Damage	Defeat fourth boss.
One after another...	Complete the boss rush.
One Head Becomes Three.	Defeat third boss.
Thirty Monster Kill Streak	Kill Thirty Creatures without getting hurt.
Up Your Arsenal	Purchase every weapon and ammo type.