Sometime in the future, the natural cycle of life and death has been broken. The undead rise and four powerful demons known as Immortals take up residence in Istrakan. San Miguel, the City of the Sun, has become a place of darkness. The world's most powerful vampire hunter has fallen, and it's up to his son Django, the heir to the Gun del Sol (a solar gun) to finish his father's work. He is accompanied by Master Otenko, a spritely sunflower who gives him advice at special hint panels.
Boktai's core game design could be described as a 1:1 mixture of Zelda and Metal Gear Solid. It takes place from an isometric perspective, giving the player an overview of the surrounding environment. Pressing and holding the R button allows you to look beyond the immediate screen to see if there are enemies in your vicinity. Similar to Solid Snake, Django must use stealth to infiltrate an area, and he has the ability to flatten up against walls and tap them to attract an enemy's attention. Different enemies react to sounds in different ways; Mummies (for example) are very fast and will quickly hone in on a sound's position, but are otherwise completely blind. Undead zombies can be tricked like typical Metal Gear grunts. Django can run, and shoot enemies using the Gun del Sol, which relies on solar-powered batteries for ammunition.
The game's areas are presented in a map screen, broken up into small dungeon-like levels in between larger boss dungeons. These are timed and scored similar to Metal Gear, in that you will lose points if you are spotted by an enemy and if you take too long. There are also trap rooms that are somewhat similar to the VR Missions. Dungeons are crawling with enemies and puzzles block the path (such as traditional block-pushing puzzles). A variety of elemental puzzles (ice and lava) also pose unique challenges.
Unique to the Boktai series is the built-in solar sensor, which is used throughout the game for a variety of purposes. To begin with, the game asks you to enter your specific time and time zone. The game uses this information to sync with the real world, so it knows if you are playing during daylight hours. This is significant because Django's gun can only be recharged by standing in direct sunlight and holding up his gun, and enemies are generally weaker or in hiding. How quickly your gun charges depends entirely on the amount of sunlight registered by the sensor. A mid-to-low range is best, as too much sunlight will cause the gun to overheat (this is likely to prevent you from getting sun stroke!). Even when you're deep inside a crypt, there may be skylights that allow sunlight to trickle in which can be used mid-dungeon. Bosses in particular cannot be killed until day time (more on bosses below).
At night, Django can charge his gun if he uses a solar station, though its power may be limited or costly. Small fireflies (only visible at night) appear which will also slightly refill your solar batteries. Enemies such as the undead become active and begin prowling the corridors, so the game becomes more difficult at night, but it is still possible to get most things done with the exception of eliminating bosses.
The bosses are similar to those in Metal Gear or Zelda, requiring quick pattern recognition skills and unique strategies. True to their name, the Immortals are only weakened after the fight, and become trapped in a coffin. The coffin must then be physically dragged out of the Immortal's lair and into the light of day where the Immortal can actually be killed. If the coffin is left alone, the Immortal inside will rustle inside the coffin, nudging themselves away while attracting the attention of enemies which will drag it back to their resting place. Although dragging the coffin outside may sound like a chore, the level designers have kept this in mind so that on your way out there are often short cuts.
Once outside, Django places the coffin the center of the Solar Piledriver. This is a series of mirrors which flip up and focus the sun's rays directly at the coffin. Once the process begins, the Immortal's demonic soul pops out of the coffin and fights back, attempting to flip the mirrors away. Django must dodge their projectile attacks and keep the Solar Piledriver charged up and focused on the Immortal, and eventually the Immortal will die - permanently.
Items & Equipment
You'll find perishable items such as apples which can restore your health or power up your gun's solar batteries. There are also items like solar flares which cause the sunlight meter to fill up regardless of the time of day.
The Gun del Sol is a complex piece of equipment with a variety of customizable pieces. Lenses focus the light into a shot or spread. The bigger the lens, the more powerful the attack. Extra battery tanks allow you to store more solar energy, which means you won't have to recharge as often. Grenades (L button) provide secondary fire. And the gun frame itself can change the type of attack; converting into elemental-type attacks (fire, earth, ice).
Boktai features a multiplayer death-match mode for 2-4 players (each player requires their own Boktai cartridge). Battles are timed, and the player with the most kills, the most coins collected, and the least deaths will be ranked on top. Players can also exchange items with one another.
Azure Sky Tower
Once the player has finished the game, they can visit the Azure Sky Tower, which is somewhat of a throwback to the PS1 Konami title Azure Dreams. The player must climb the tower solving puzzles and killing enemies, until they reach a certain floor where they fight a knight. Killing the knight will unlock one of several emblems.
Sequels & Criticism
Out of the four Boktai games, only Boktai 3 remained a Japanese exclusive. The 4th game moved the series onto the Nintendo DS, and was retitled Lunar Knights, though it lacked a solar sensor (and thus its functionality).
Some players complained that the solar sensor related "gimmicks" were a burden at best and annoying at worst. For best results the game is best played outside. However, Boktai's bosses cannot be defeated at night, forcing players to adhere to a certain play schedule, and the game becomes almost unplayable during bad weather and in the winter in some areas due to the overcast skies.