Here is the full list of all 69 DEEP SPACE WAIFU achievements. It takes around 1-2 hours to unlock all of the achievements on Windows.
Play with all the girls
Unlock NEKOTINE
Beat MOKOTO with one hand
Play one hand mode with MOKOTO
MOKOTO naked
60% of clothes off MOKOTO
Beat NIKITA with one hand
Play one hand mode with NIKITA
Beat TOMOKO with one hand
Play one hand mode with TOMOKO
Beat MITSUMI with one hand
Play one hand mode with MITSUMI
Beat MISAKO with one hand
Play one hand mode with MISAKO
NIKITA naked
60% of clothes off NIKITA
30% of clothes off NIKITA
Unlock ARISA MIKEA
Gain 18 stars
Beat the ARMORY boss
MISAKO naked
60% of clothes off MISAKO
30% of clothes off MISAKO
Unlock MISAKO AOYAMA
Unlock NIKITA DORMER
TOMOKO naked
60% of clothes off TOMOKO
30% of clothes off TOMOKO
Beat the SAMURAI boss
Unlock YUMI MATSUDA
MITSUMI naked
30% of clothes off MOKOTO
60% of clothes off MITSUMI
30% of clothes off MITSUMI
See the credits
Beat SARAH with one hand
Play one hand mode with SARAH
Unlock one hand mode
Unlock MITSUMI KATAGIRI
Date with a girl
Beat the VULCAN boss
Gain 5 stars in one girl
SARAH naked
60% of clothes off SARAH
30% of clothes off SARAH
Explode your first piece of clothes
Play the dating app
Beat the PLAGUE boss
30% of clothes off YUMI
60% of clothes off YUMI
YUMI naked
Play one hand mode with YUMI
Beat YUMI with one hand
30% of clothes off ARISA
60% of clothes off ARISA
ARISA naked
Play one hand mode with ARISA
Beat ARISA with one hand
30% of clothes off NEKOTINE
60% of clothes off NEKOTINE
NEKOTINE naked
Play one hand mode with NEKOTINE
Beat NEKOTINE with one hand
Unlock REMI TACHIBANA
30% of clothes off REMI
60% of clothes off REMI
REMI naked
Play one hand mode with REMI
Beat REMI with one hand