Mission Mermaiden Hasumi And The Deep Sea Sis Free !!install!! -

is a niche 2D side-scrolling action platformer released by circle Project Firefly on DLsite. Set in a dystopian sci-fi world, the game combines retro combat mechanics with mature (18+) narrative elements.

Note: A 64‑bit system is required; 32‑bit Windows is not supported.

Trafficking, Hasumi realized with a chill. They’re turning divers into these things. mission mermaiden hasumi and the deep sea sis free

Official publisher, original Japanese version, points system, frequent sales. Credit Card, PayPal, BitCash

The game takes place in the year . The world has been completely ravaged by a devastating alien invasion, leaving human civilization in ruins. is a niche 2D side-scrolling action platformer released

The character sprites and backgrounds are saturated with color, bringing the coral reefs and abyssal plains to life.

In line with its 18+ adult classification, failing in combat or being captured by certain enemies triggers specific adult-oriented cinematic scenes, which serve as both a penalty and a core feature for fans of the genre. Graphic Style and Presentation Trafficking, Hasumi realized with a chill

The core narrative focuses on the relationship between Hasumi and her sister. You don't just play as one character; you often utilize "echoes" of the sister to solve complex environmental puzzles. Exploration and Upgrades

Stick to Steam, Itch.io, or the Epic Games Store.

The game includes reworked "bad endings" and a revised escape system that forces players to make tricky decisions during capture scenarios.

: Secret rooms containing health restoratives, ammo upgrades, and gallery unlocks are often hidden behind destructible or false walls.