In the Iki Island expansion, there is a special Horizon Forbidden West-themed armor set that can be obtained at the Forbidden Shrine. At the shrine, there is a scroll containing a poem hinting at how to do so. Spoiler:The player must equip Tadayori's armor and activate focus hearing to reveal 3 targets along the shrines statue: one above it's head, another on its hand, and the last on the head of a demon that the statue is standing on. Once completed, the corruption wrapped around the statue falls away and the player receives said armor

The corruption wrapped around the statue is a reference to all the corruption tainting the land and machines in Horizon Zero Dawn and Horizon Forbidden West.

In the Iki Island expansion, there is a special Bloodborne-themed armor set that can be obtained at the Blood-Stained Shrine. At the shrine, there is a scroll containing a poem hinting at how to do so. Spoiler:The player must take damage in front of the shrine before equipping the Kensei armor and healing themselves, this will unlock the Yharnem armor.

At the base of the shrine there is also a painting of a giant red circle with black birds flying in front of it. This is a reference to the giant blood moon featured throughout Bloodborne

In the Iki Island expansion, there is a special Shadow of the Colossus-themed armor set that can be obtained at the Shrine in Shadow. At the shrine, there is a scroll containing a poem hinting at how to do so. Spoiler:The player must equip the Ghost armor and thrown down a smoke bomb in front of the shrine to obtain this armor set.

The shrine is also adorned with a glowing symbol and some fur patches, two characteristics that are seen on every colossi throughout the referenced game, Shadow of the Colossus

In the Iki Island expansion, there is a special God of War-themed armor set that can be obtained at the Shrine of Ash. At the shrine, there is a scroll containing a poem hinting at how to do so. Spoiler:The player must equip the Sakai Clan armor and perform the action for unsheathing their sword in front of the shrine to obtain it.

There is also an ash tree with a golden hand print planted near the shrine, a direct reference to the intro for God of War.

Laying along the base of the statue are piles of chains, these are a reference to the chains that hang from the hilts of one of Kratos signature weapons, The Blades of Chaos.

There is a hidden questline in the game that is not trackable and only progressed by finding letters, each one a Key Item referred to as "A Family's Escape", hinting to where the next one would be. This questline follows a family that is fleeing the island of Tsushima who are leaving notes for an unaccounted family member named "Toku". Spoiler:The fate of the family and of Toku are left ambiguous by the quest's end.

Toshihiro Nagoshi, the general director of the Yakuza series, was awestruck by Ghosts of Tsushima and its depiction of Japanese culture, history, and aesthetic, even going so far as to say that it was something they (Japanese game developers) should've made. He furthermore said it broke the misconception that western people do not understand Japanese culture.