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