Works out of the box with some minor issues that can be mitigated:

Controls

Issue: There is gamepad support, but unfortunately the game will still display keyboard inputs. Even worse, there doesn't seem to be anywhere in-game that lists the controls to help with remapping.

Solution: A user named My1 has created a guide in the Community tab which documents the controls for both keyboard and PlayStation controller. You can continue to use game pad control settings, or map the keyboard controls within Steam if you wish.

Sprite Scaling

Issue: Out of the box, the sprites look horrendously aliased during visual novel scenes due to scaling issues caused by an in-game setting. This is further exacerbated when connected to an external display as the resolution cannot be configured in-game.

Solution: To fix the in-game setting, launch the game and select New Game (options cannot be configured from the title screen so we have to get to gameplay in order to actually make changes). Use the Tab key or Start button to skip all of the initial scenes until you are able to move around in the tutorial dungeon. Now press Tab or Start to open the menu, and use the E key or Right Bumper to get to the "Option" tab. Now change the Screen Size setting to Full. Exit the menu with the N key or Circle/B button. Now you can exit the game and select New Game again to watch the opening scenes with much better sprites.

If using an external display, go into the game Properties on Steam and change the resolution to Native. This will clean up the sprites just a bit more.