Here is the full list of all 69 Deep Space Waifu: FLAT JUSTICE achievements. It takes around 2-3 hours to unlock all of the achievements on Windows.
complete ONE HANDED SPY
Complete ONE HANDED MILF
Complete ONE HAND PUCKY K-9 UNIT
Complete ONE HAND MIKA
Complete ONE HAND JULIA
Complete an ONE HANDED SALE
Finish with the M.I.L.F.
Defeat Dickus final form
100% M.I.L.F.
Use the JUSTICE LASER special attack
Infiltrate in the secret TENTACLE organization
Destroy the Sneak Mothership
complete 100% the spy
Complete ONE HAND SERGEANT CHIKARA
Defeat DP Miner
100% SERGEANT CHIKARA
Complete ONE HAND LIME CODE
Get the super scret spy business card
Reach 30 STARS
Defeat Dickus third form
100% LIME CODE
Be spotted by the enemy
Complete ONE HAND NORMAL ROCKY CHAN
Complete NORMAL ROCKY-CHAN
Defeat the Thrasher Super Mecha Warrior
Unlock LIME CODE
Get the F.L.A.T. Multipass badge
Defeat Dickus second form
100% PUCKY K-9 UNIT
Defeat DP Mothership
Complete ONE HAND METAL ROCKY CHAN
100% METAL ROCKY CHAN
Complete ONE HANDED SHARP-EYE
Get promoted to the F.L.A.T. SPECIAL FORCES
Get a smelling Pantie evidence
Reach 18 STARS
Complete SAYRU-CHAN
Defeat the Fake Wadding
100% SHARP-EYE YUMIKO
Explode a mine!
DATE all girls
Unlock NORMAL ROCKY-CHAN
Unlock PUCKY K-9 UNIT
Unlock SERGEANT CHIKARA
Unlock M.I.L.F.
Find the PERFECT FLATNESS
Unlock the SECRET SPY
Complete ONE HAND NAO
Get a special Phone Number
Defeat Dickus first form
100% JULIA SUZUHARA
Unlock METAL ROCKY-CHAN
Reach 10 STARS
Unlock SAYRU-CHAN
Defeat DP Defender
100% NAO NEKOYAMA
Get the RAY power up
Get the SHIELD power up
Unlock SHARP-EYE YUMIKO
100% MIKA MOKOTO
Make a 5 STARS stage
Get the MACHINE GUN power up
Take a photo of a girl
Kick Justice in the balls
Get the LASER power up
Torn apart your first piece of cloth
Get the ROCKET LAUNCHER power up
Go to your first date
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