Vampire Rain is a stealth game similar in nature to the Splinter Cell or Metal Gear series. Players are tasked with navigating their character through city streets, while avoiding the vampire enemies that patrol the streets disguised as ordinary human citizens. Players often have to take alternate routes, such as climbing onto rooftops or through alleys, to avoid enemy encounters.
Unlike most stealth-action games, Vampire Rain places heavy emphasis on pure stealth. Enemies are extremely fast and can kill the player in two hits; the first hit usually immobilizes the player, giving the vampire sufficient time to land a second, killing blow. Additionally, for the first third of the game, players lack any weaponry that can kill vampires effectively without spending a large amount of ammunition. In effect, most attempts to initiate combat generally result in the player's death. Also, unlike most stealth games, there is usually no effective means to hide or escape once an enemy has spotted the player, which results in the player dying soon after being spotted. Successful completion of many missions thus generally requires total avoidance of enemies by figuring out the correct route to pass through the mission area without being detected.
Later in the game, players are given high-powered weapons which prove more effective against the game's vampire enemies. Also, there are a few pre-scripted action sequences that involve fighting against multiple enemies, generally with the assistance of teammates or special environmental hazards. The player's arsenal includes a handgun, submachine gun, assault rifle, shotgun, sniper rifle, anti-armor rifle and a UV Knife used to stab an enemy from behind for an instant kill.
If the player collects enough "Medals" that are either placed in hidden or difficult to reach spots throughout the game as well as passing certain missions under certain conditions such as within a time-limit, without needing to retry from a checkpoint or without killing any Nightwalkers will reward the player with extra side-missions and challenges.
Online multiplayer involves up to eight players in standard modes such as deathmatch, team deathmatch and capture the flag, as well as the unique mode which allows one to become a nightwalker and fight opponents with extreme speed and power. All the firearms are available online and the gameplay is handled like in single-player.