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