Here is an overview of the game, via its Steam page:

About

The Devil Within: Satgat is a 2.5D stylish action adventure that follows the journey of an Eastern warrior infected with demonic blood. Dig into the secrets of a ruined world while taking down enemies in stylish action sequences.

With the mysterious arrival of the Black Stone Tower, the once peaceful world of Joseon was changed forever. The energy emitting from the tower initially brought prosperity to the lands, but as the power grew, evil spirits emerged and took over the living. Mighty warriors tried to stop the invasion by destroying the tower, but an unfortunate betrayal led to their failure.

Key Features

• Search For Hope In A World Of Despair – The world has been destroyed, and most living beings have become evil spirits that wander from place to place. Play as Rip Kim, a mysterious warrior who’s the last of his kind. Only he can find and guide the lost souls, who may still have humanity, to a resting place.
• Fight Fierce Battles – It’s up to you to eliminate the demons that have crawled into this world. Fight powerful demons with the use of swordsmanship and shooting skills that you upgrade throughout the game. Only the strongest humans can survive the battle and save mankind.
• Accept the Power Of Evil Spirits – As you progress throughout the game, a dark truth becomes clear: the best way to kill evil spirits is by becoming one yourself. With every spirit you extinguish, that dark power transfers to you. Journey further into the unknown lands to discover clues to help you control your body as it becomes increasingly evil.
• Discover the Secrets Of A Dark World – The mysterious Black Stone Tower has changed everything. Explore a mysterious world full of secret locations and powerful artifacts. But be careful with what you find, as some secrets may come with fatal consequences.
• Vast Interconnected World – Explore an intricately connected world with diverse locations including ruined cities, rocky mountains, dense forests, military bases, and more. As you venture through these areas, some paths may be blocked until you’ve become strong enough to move forward. Take down ferocious enemies to make it to the next level alive. Explore each area thoroughly to unlock upgrades and abilities to make you more and more powerful for the challenges ahead.

Watch the announcement teaser trailer below. View the first screenshots at the gallery.

Announce Teaser Trailer

Instrumental Version

Vocal Version