Here is the full list of all 71 Heart&Slash achievements.
BEAT THE UNBEATABLE
TOGETHER WE RISE
DEFEAT YOUR FIRST C.O.P.S. FLASHBANG
DEFEAT FIFTY SMALLBOTS WITH A FREEZER BACKPACK
DEFEAT ALL BOSSSES IN THE FACTORY AND THE CITY
LONG LIVE THE QUEEN
DEFEAT FIFTY LASER ARMED ENEMIES
DEFEAT TWENTY FIVE TRIPODS
DEFEAT TWENTY FIVE WORMS
DEFEAT ONE OF EACH ENEMY CARRYING A BLADE OR A SAW
UNLOCK ALL BLADES
DEFEAT TEN WORMS
SIDE WITH SLASH IN THE FIGHT AGAINST QUASSY
DEFEAT FIFTY ARMOURED ENEMIES
DEFEAT FIFTY SMALLBOTS WITH A BACKPACK
BAT FIFTY MISSILES
UNLOCK ALL AXES
DEFEAT ONE HUNDRED SCAVENGERS
DEFEAT TWENTY FIVE SMALLBOTS IN THE CITY
DISPLAY YOUR COMMITMENT
SURVIVE FIFTY ARENAS
BEAT QUASSY AND UNCOVER THE TRUTH
DISRESPECT THE AUTHORITY
EQUIP YOURSELF COMPLETELY
DEFEAT ONE HUNDRED BIGGRUNTS
DEFEAT FIFTY C.O.P.S. ENEMIES
DEFEAT YOUR FIRST MAGNET
FIND SLASH IN THE OUTSIDE WORLD
REACH FIFTEEN HEARTS OF MAX HEALTH
DEFEAT TWENTY FIVE ENEMIES WITH A BACKSTAB
UNLOCK ALL FIST BASED WEAPONS
COMPLETE ALL THE QUESTS IN THE FACTORY
HELP SLASH EXIT THE FACTORY
USE YOUR HEAD AND SAVE SLASH
DEFEAT FIFTY ELITE ENEMIES
CLEAN THE REMNANTS
DEFEAT ONE HUNDRED NIMBLEBOTS
DEFEAT ONE HUNDRED SMALLBOTS
DEFEAT TWENTY FIVE ARMOURED ENEMIES
HAVE YOUR ENEMIES DEFEAT TWENTY OF THEIR OWN
SURVIVE SLASH'S CHALLENGE
DEFEAT TWENTY FIVE LASER ARMED ENEMIES
DEFEAT FIVE TRIPODS
DON'T BE MEAN
JUMP A THOUSAND TIMES
DEFEAT FIFTY SHIELDED ENEMIES
DEFEAT ONE HUNDRED FLYBOTS
SURVIVE THE DOCTOR'S CHALLENGE
DEFEAT YOUR FIRST TRIPOD
SURVIVE TEN ARENAS
EXPLORE ONE HUNDRED ROOMS
DEFEAT TWENTY FIVE BIGGRUNTS
DEFEAT THE GUARDIAN
DEFEAT TEN LASER ARMED ENEMIES
SURVIVE FOR TWENTY MINUTES
DEFEAT TWENTY FIVE SMALLBOTS
DEFEAT TWENTY FIVE NIMBLEBOTS
DEFEAT TEN BIGGRUNTS
DEFEAT TEN SMALLBOTS
DEFEAT TWENTY FIVE FLYBOTS
DEFEAT TEN FLYBOTS
DEFEAT TEN NIMBLEBOTS
UPGRADE A WEAPON AND LET THE GOOD DOCTOR KNOW
DEFEAT YOUR FIRST SHIELDED ENEMY
CREATURE OF THE NIGHT!
DEFEAT TWENTY OF EACH DOG'S PARTS
DEFEAT FIFTY WORMS
DEFEAT FIFTY SMALLBOTS WITH A FIRE BACKPACK
FINISH A LEVEL UNSCATHED
BEAT QUASSY WITH A FULLY UPGRADED RUBBER DUCK
BEAT QUASSY WITH THE PROTOTYPE