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