10 minutes of gameplay footage for a Sucker Punch game called Prophecy has leaked. The footage originated on Resetera and looks to be the game that Sucker Punch were working on before Ghost of Tsushima.
The game looks to be set in Medievil times, and actually features swordplay similar to that of Ghost of Tsushima. The game looks like it would have been more linear like other Sony first-party titles, and even features first-person crawling, like Ghost of Tsushima does.
The combat has one key difference to that of Ghost of Tsushima in the sense that the main character looks to have a powder substance that can melt through objects in the environments as well as the metal armour of guards.