Gameplay
A unique feature of Boktai is that before a game is started, the player is prompted to set their current time and time zone. The engine can then determine when the sun will rise/set, and will simulate the position of the sun inside the game. This way, the player has an advantage during the daytime because, according to lore, vampires cannot be exposed to sunlight. Sunlight also affects the world around the main character. A good example is the Solar Tree. This tree is affected by all the darkness of the Immortals, and can be cured by playing in sunlight. The game also simulates times of day by putting bird chirp sound effects in the morning, and giving the outdoor environment a soft orange glow around sunset.
Unlike other action RPGs, the combat focuses on stealth. An integral concept is shooting an undead in the back, stunning it then running away or finishing it off. Getting caught by a monster (indicated by a red exclamation point above the head) will reduce the grade received at the end of a stage. The highest grade one can receive is an "S", and the lowest an "C-". A number of other factors also determine the grade received, such as total time taken to complete the level. While playing the game, the player goes through a number of levels called dungeons. After a certain amount of these dungeons, the player will encounter a level that somewhat bigger than the others. These levels all called Immortal, because the four Immortals reside inside these levels. The player will have to fight his way to the so-called boss creature, or Immortal, of the level. The player must defeat the "Bosses" and return them outside the dungeon level, to bathe and battle the Immortals into sunlight, called a Battle Drive (this is from the name of the device, used to defeat the Immortals, called the Pile Driver, summoned by Master Otenko). The player must use the solar sensor inside the game pack to defeat the Immortal. The sunlight will activate the Pile Driver. The Pile Driver will shoot the amount in sunlight to the Immortal. The Immortal will get weakened faster if the amount of sunlight is higher.
The "Gun del Sol" is the only weapon used by the main character. It has the ability to charge with sunlight and being the only weapon to defeat the undead and Immortals. It is a very versatile weapon, because all parts of the gun (lens, frame, battery, and grenade) can be customized. By changing the Lens, the element used by the Solar Gun will be changed. There is a wide choice of lenses, Sun, Luna, Fire, Frost, Earth, Cloud, Dark and Star. They all have different effects at different situations. Some monsters have specific weaknesses against an element. As you use the lenses, they will gain experience and if it gains enough experience, the lens will become stronger and level up. This will increase damage and effectiveness. Some element lenses (Fire, Frost, Earth and Cloud) will be used to solve puzzles. A frame is the part that will determine the shots of the gun. The gun's fire can be changed by adding different sorts of Frames. Some of the frames are inspired on existing weapons (shotgun, automatic gun) and some are fantasy based (a sword spread, a vortex or a wide spread). They have their own strength, based on grades from C- (weakest) to A (strong). Batteries are the gun's power source. By increasing the quality of the battery, the gun will be able to store more energy from the sun. Grenades are explosives with different types of effects. Some will explode, attracting or hurting enemies and some will be able to reveal hidden objects.
Read more about this topic: Boktai: The Sun Is In Your Hand