Project: Divine Comedy

The whole Purgatory is accessible through this door, located inside a Cathedral.
The player has to follow a 'cross' path, to open the door:
- first to the left, he must interact with the 'muted' statue, melt the finger to get the stone
- after the finger is melted, the first two statues pierce the praying one
- second, he must go to the right and interact with the 'blind' statue by placing the stone on the marvel pillow
- after the stone is placed, the remaining statue on top of the door activate: piercing the statue below and breaking the praying statue causing the door to open. 

The player encounters various enemies during the game, and the Archangels are some of them. These entities have stones embed in their fingers, that they use to open doors scattered across Hell, Purgatory and Heaven.

This is the area of Hell where the heresiarchs are punished, described by Dante in Canti VIII, IX, X and XI. It is contained within the hellish city of Dite, looking like a city with fire-red and reddish domes, towers and walls. 

Charon is the Ferryman of Hades. The player can use him (and only him!) to move around Hell and Purgatory. The old man/gondola must be paid with specific coins, or he won't move.

In the whole game, baptismal fonts are scattered around, full of holy water and serve as respawn points. This one in particular is located in a small hut on the river Stix, inside a swamp area. The hut allows the player to restore hp, save, modify/fix weapons and improve his skills.

One of (if not the most) the powerful bosses in this game, Lucifer is stuck in his pit, unable to move. When he fell from Paradise, his body (pierced by Longinus spear) started mutating and became a headless monster with multiple arms and tentacles. Lucifer's original body can be seen on top of this beast, with the ghost bounded to the holy spear, unable to move as well.

The Castle of Spiriti Magni is one of the first places Dante goes to, a place for pagans who distinguished themselves particularly in life but yet, not allowed to go to Paradise. The castle is surrounded by a halo of light, seven of walls and water. In my take, the place gets colder the closer you get to the ground, the castle floats and is reachable only by a sort of cable-car/cage.

The castle is full of merchants and a rest area, the player can visit the place to purchase all kinds of stuff, and to speak to the souls 'working' there (ex: Homer acting as a blacksmith, selling the weapons of the books he wrote like the Odyssey).

Last but not least: Virgil. 

In the poem, Dante goes around with Virgil (a fellow poet) who appears in Canto I of Hell, leading him on a journey through two of the three kingdoms of the Underworld (Hell and Purgatory).
Following the same concept, Dante founds an half-dead Virgil and manages to bound his soul on the disk using Necromancy and manages to build the whole instrument inside his skull, putting seals in the eyes as an additional measure of safety. Even if played, not always Virgil reacts positively, and only helps the player in specific places while mocks him the most of the time.