Seabase Delta is a text adventure with graphics that was developed using the Quill game writing software package.

This game is a sequel to the game Subsunk. The previous game saw the player, in the role of Ed Lions, aboard a submarine that had been sunk by enemy powers. The task there was to send a message back to base requesting help.

This game picks up from that point. The enemy have intercepted the message and, using a mysterious magnetic force, have taken the submarine to their underwater base. The player, again in the role of Ed Lions, starts the game in a walkway to the base. Beside him is a dead body and a briefcase. Ed must explore the base and find a way to escape.