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.
Beat TOMOKO with one hand
Play one hand mode with TOMOKO
Unlock one hand mode
Beat the VULCAN boss
SARAH naked
Gain 5 stars in one girl
60% of clothes off SARAH
30% of clothes off SARAH
TOMOKO naked
60% of clothes off TOMOKO
Date with a girl
Beat the SAMURAI boss
30% of clothes off TOMOKO
Explode your first piece of clothes
Play the dating app
Unlock MITSUMI KATAGIRI
Unlock NIKITA DORMER
Unlock YUMI MATSUDA
Unlock MISAKO AOYAMA
Unlock ARISA MIKEA
Unlock NEKOTINE
Unlock REMI TACHIBANA
See the credits
Beat the ARMORY boss
Beat the PLAGUE boss
Play with all the girls
Play one hand mode with SARAH
Beat SARAH with one hand
30% of clothes off MOKOTO
60% of clothes off MOKOTO
MOKOTO naked
Play one hand mode with MOKOTO
Beat MOKOTO with one hand
30% of clothes off MITSUMI
60% of clothes off MITSUMI
MITSUMI naked
Play one hand mode with MITSUMI
Beat MITSUMI with one hand
30% of clothes off NIKITA
60% of clothes off NIKITA
NIKITA naked
Play one hand mode with NIKITA
Beat NIKITA with one hand
30% of clothes off YUMI
30% of clothes off MISAKO
60% of clothes off YUMI
MISAKO naked
YUMI naked
Play one hand mode with YUMI
Play one hand mode with MISAKO
Beat YUMI with one hand
Beat MISAKO 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
30% of clothes off REMI
60% of clothes off REMI
REMI naked
Play one hand mode with REMI
Beat REMI with one hand
Gain 18 stars
60% of clothes off MISAKO