The mechanic of communicating though chirping was partially inspired by Shadow of the Collossus. Specifically, Wander communicating with his horse Argo, yielding different reactions depending on how hard the button is pressed, or current circumstances.
Johnson felt having short pieces of music that looped without reacting to the player would be a "missed opportunity", and wanted to create music that changed while still containing a composed emotional arc. Creative Director Jenova Chen met with Wintory at the start of the game's development to describe his vision for the project, and Wintory left the meeting and composed and recorded the main cello theme for the soundtrack that night. He continued to work on the soundtrack for the next three years, experimenting and discarding many ideas.
The music in Journey was composed by Austin Wintory, who also worked with thatgamecompany on the soundtrack for FlOw. Wintory worked closely on the soundtrack with sound designer Steve Johnson, as well as the programming team, so the music would dynamically tie in to both the actions of the player and sound effects caused by nearby game objects, and feel as if it were "unfolding in real time".
Development of the game began with a team of seven with a one year deadline from Sony, which was expanded to 18 people and an additional two years in development. The team always expected needing an extension, believing finishing the game within a year was "unrealistic".
The multiplayer component of Journey was designed to facilitate cooperation between players without forcing it, and without allowing competition. It is intended to allow the players to feel a connection to other people through exploring with them, rather than talking to them or fighting them. The plan was "to create a game where people felt they are connected with each other, to show the positive side of humanity in them." The developers felt the focus on caring about the other player would be diluted by too many game elements, such as additional goals or tasks, as players would focus on those and "ignore" the other player.
The basic idea for the game, as designed by Chen, was to create a game that moved beyond the "typical defeat/kill/win mentality" of most video games. The team initially created a prototype named Dragon that involved players trying to draw away a large monster from other players, but eventually discarded it after finding it was too easy for players to ignore each other in favor of their own objectives.
In the The Desert area there is a flower growing out of the sand. This is an easter egg referencing the developer's earlier release, Flower.
After filling the column area in the Temple with mist, a "mysterious creature" will appear in either the lowest section of the column or behind the curtains of a hidden area (which ever the player searches first). This creature is one of the playable organisms from flOw.