Here is the full list of all 25 Solas City Heroes achievements.
Complete Area 1
Complete a stage with a maximum combo of 30 or more
Complete Area 2
Complete Area 3
Complete Area 4
Complete Area 5
Complete Area 6
Defeat 500 enemies
Defeat 2000 enemies
Defeat 5000 enemies
Reach corruption level 10
Reach submission level 10
Win a survival match that last 9 minutes or more
Unlock all Specials at the same time
Unlock 50 cloth pieces on a single character
Unlock 100 cloth pieces on a single character
Unlock 200 cloth pieces on a single character
Reach max level and unlock all the upgrades on the shop
Obtain all the enemy and boss data on a single character (excluding bonus enemies and bosses)
Unlock all the base sex positions on a single character
Complete all stages with the hardcore setting enabled on a single character
Get fully restrained 25 times
Be captured 20 times...
Defeat 50 boss enemies with a single character
Cum over 200 times on a single character