Complete the indicated task to unlock the achievement.

Achievement	How to unlock
Airborne for 60 Seconds	Airborne for 60 Seconds.
Collected All Weapons	Collected All Weapons.
Killed 13 Hammerheads	Killed 13 Hammerheads (ever)
Killed 13 Skull Mechs	Killed 13 Skull Mechs (ever)
Killed 6 Enemies in Single Explosion	Killed 6 Enemies in Single Explosion.
Killed 666 Enemies	Killed 666 enemies (ever)
Reached Wave 10	Reached Wave 10.
Reached Wave 20	Reached Wave 20.
Reached Wave 30	Reached Wave 30.
Reached Wave 40	Reached Wave 40.
Reached Wave 50	Reached Wave 50.
Reached Wave 60	Reached Wave 60.