Here is the full list of all 69 DEEP SPACE WAIFU: FANTASY achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
COMPLETE ONE HAND AUGEMEISTER
100% AUGEMEISTER
COMPLETE ONE HAND SONJA
FIND THE CLITORIUS
DEFEAT BRAINHOLDER
100% SONJA DRAGONTOOTH
COMPLETE ONE HAND OPHELIA
DEFEAT THE MOAI ANGEL
100% OPHELIA
COMPLETE ONE HAND MODE TRICCIA
DEFEAT ASMODEUS
100% TRICCIA
COMPLETE ONE HAND ABYSSAL
RESCUE THE PRINCESS FIERNA
EXPLORE ALL OF THE HENTALIA CONTINENT
UNLOCK THE DRAGON
REACH STAR LEVEL 35
DEFEAT SATAN
100% METAL ABYSSAL
COMPLETE ONE HAND TIA SOFTHAND
DESTROY THE DEVIL MINIBOSS
UNLOCK THE SWORD ABILITY
UNLOCK AUGEMEISTER
DEFEAT THE KNIGHT SKULL
100% TIA SOFTHAND
COMPLETE ONE HAND RYA
UNLOCK THE EXTRA SHOOTING POWER
UNLOCK SONJA DRAGONTOOTH
REACH STAR LEVEL 25
DEFEAT THE UGLY FAERIES
100% NORMAL RYA TUTORIALICCA
UNLOCK THE FILLED SPECIAL BAR
UNLOCK OPHELIA
COMPLETE ONE HAND MODE OROCHI
UNLOCK THE UNICORN
UNLOCK TRICCIA
DEFEATS TENTACLE MOON
100% OROCHI THE NAGA
UNLOCK THE EXTRA POWER UP SLOT
REACH STAR LEVEL 15
FIND A RANDOM ENCOUNTER
COMPLETE ONE HAND MODE CARSSIA
UNLOCK NORMAL RYA TUTORIALICCA
100% CARSSIA BORGOTH
DEFEAT VIKING
COMPLETE ONE HAND MODE RENA
UNLOCK THE PROTECTIVE HELMET
UNLOCK TIA SOFTHAND
UNLOCK METAL ABYSSAL
REACH STAR LEVEL 10
DEFEAT THE DEVILANGEL SUB BOSS
100% RENA GREENLEAF
UNLOCK THE BANDANA
SKIP ONE OF OUR EMOTIONAL CUTSCENES
COMPLETE ONE HAND MODE JELLY
DESTROY THE ANGEL MINIBOSS
SEE THE CREDITS!
YOU ENTERED GALLERY MODE
UNLOCK OROCHI THE NAGA
GET 5 STARS IN ONE STAGE
TAKE A PICTURE OF A GIRL IN MIDDLE AGES
DEFEAT THE SLIME SUB BOSS
100% JELLY-CHAN
REACH STAR LEVEL 5
YOU DIED IN A DATE
EXPLODE A PIECE OF CLOTH
HAVE YOUR FIRST DATE
PRESS START
UNLOCK CARSSIA BORGOTH