Subsurface Circular

Subsurface Circular is a text-based adventure game set aboard an underground train. The game consists of seven sequences, unlocked gradually, and the entire game is built around conversations. The player's character is a robot detective tasked to investigate a number of disappearances. The robot sits aboard the train for the entire game and engages in conversations with robot passengers as they get on and leave at different stops.

During conversations there are usually multiple dialogue options leading to different reactions. The game is linear in design, but the player needs to figure out a number of puzzles based around choosing the right conversation options to keep progressing. Through certain interactions focus points are unlocked. Those are themes or events that can be used to interrogate different passengers and they are carried over between sequences.