Soul of Darkness is a side-scrolling action game that bears much resemblance to the modern Castlevania games in the way of tone and art style. It also employs a mini-map feature that is similar to those found in said Castlevanias as well as Metroid, but the progression is much more linear than the "Metroidvania" norm. It has been criticized for being too similar to Castlevania specifically with regards to the aforementioned minimap, its gothic-horror vampire trappings and its overall aesthetic (with the protagonists' look-and-feel and animations resembling those of many of the modern-era Castlevania protagonists).
Soul of Darkness is pretty straightforward in its gameplay, delivering 2D platforming and hack-and-slash combat through which your character will deliver simple multi-hit combos. Game progression takes place in clearly distinguishable levels with boss encounters at the end of each.
Soul of Darkness does offer a leveling system that allows you to improve your attack combos, attack power, and magical power through the use of experience orbs not unlike those found in God of War, Ninja Gaiden and Devil May Cry. The game also makes use of the DSi camera in certain areas. Certain rooms prompt you to take a picture of your surroundings with said camera, granting you orbs or health refills depending on the dominant color of the resulting photograph.