Shortly after the showcase of the remaster, Community Director of the studio, James Stevenson, took to Twitter. There he said that Insomniac has been working on it since last year, meaning the development began in 2019 at roughly this same time. While the game doubtfully had a full team on it at the scale of a normal production, that’s still quite a development cycle for a remaster. It definitely shows that some real work went into the game.
