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