This whole game plays like a homage to the classic top-down games of a bygone era, namely Zelda. For fans of that era, you can literally get your jollies to nostalgia. The Sword of Succubus has been translated into English, so there's no worry there.

Here's what Libra Heart has to say about their game:

A Retro-style Action RPG

A succubus with the holy swords in her hands sets out on an adventure!

Contains 41 Ecchi Animations in total!
28 CG!

Let's go all around the world in search of ecchi events!

[Milk System]
It is possible to let people drink her breast milk to help them!

Breast massage makes her lactate more and more!

[Prostitution System]
She can perform some erotic jobs at a bar!
The more times she has gone through, the more money she will get!

[Enchanting Spell]
She is, as a succubus, able to captivate monsters and suck their lifeforce!
Get HP and MP from enemies!

[How To Unlock Gallery]
Press the H key 20 times on the gallery screen!

The story behind this game is that the titular succubus gets a holy sword from a night, and she goes on a journey to defeat the the great evil of the game. A more interesting Link, I'd say. It was an interesting game to play. It takes from games like classic Zelda in terms of gameplay and graphics, but it's done really well.