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