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