Phantomasa is an adult 2D game about a female android. It is the third revision of the original Phantomasa game created in 1993 by the same developer. It takes places on an unknown planet in the Andromeda galaxy where an evil race mass-produces thousands of androids. The player's character is one of them and when she wakes up she becomes self-aware and sees the other androids are inactive. A mechanic rushes in and deeming her faulty, she goes in the trash. When she wakes up she is in the house of a sorcerer. He tells her there is another android like her, Phantomas, and he has managed to escape Andromeda. The android is advised to track him down and attack him with her breasts to find out the truth.
The game consists of three parts. In the first part the android needs to break into Phantomas' warehouse where his loot is stashed. It consists of nine fixed-screen room where platforming and moving blocks is required to reach the exit. Jumping is the only required action and some environment based puzzling is required to move the blocks. In the second part the computer's security system needs to be defeated through games of Rock Paper Scissors. The third and final parts takes place inside Phantomas' tower. The gameplay is similar to the first part, but now there are eight rooms and there is a time limit to complete them quickly as acid drops down filling the room and the android must progress quickly to reach the confrontation with Phantomas. There is a lengthy introduction and ending to the game with different types of screens. Ten lives are provided at the start.