Boktai

Life Fruit:
Press Up(2), Down(2), Left, Right, Left, Right, B, A when in n a room in the Abyss.

Dark Lens:
Successfully complete the game to unlock the Dark Lens.
Information in this section was contributed by michael willette.

Dark Frame:
Successfully complete the game two times to unlock the Dark Frame.
Information in this section was contributed by michael willette.

Astro Battery:
View the Pink Solar Tree as evening changes to night.

Chaos Battery:
Unlock the Pink Solar Tree under the hard difficulty setting then complete the game.

Dark Battery:
Successfully complete the game under the hard difficulty setting after unlocking the Dark Frame.
Information in this section was contributed by michael willette.

Dark Gun:
Combine the Dark Lens, Dark Frame, and Dark Battery.
Information in this section was contributed by michael willette.

Pink Solar Tree:
Get to over 1500 Sols.

Control title screen:
Vary the amount of sunlight that hits the sensor to control how fast the rays move from the sun at the title screen.

See sunrise and sunset times:
Use the following trick to see the sunrise/sunset time without entering an Immortal Dungeon. Press Start at the "Select Menu" screen. Where it normally displays the time, it instead will show the sunrise time. Press Start again to see the sunset time.
Information in this section was contributed by Ryubof.

Greater grenade capacity:
Get 9,999 points in link battle mode.

Hint: Defeating Dracula:
When you fight Dracula, go to the skylight and cover the solar sensor with you hand. Make sure that no sunlight gets into it. Then, when Dracula appears under the skylight, remove your hand from the sensor. You will drown him with sunlight, allowing an easy victory. This trick works best on a sunny day.
Information in this section was contributed by John Silva.

Hint: Defeating Boks:
Use a Spear Frame. It will either stun them for awhile or kill them.
Information in this section was contributed by Lego6410.

Hint: Defeating the Volcano Area Immortal:
First, take out the Permafrost Immortal. Although this is not easy, it will make the journey easier.
Information in this section was contributed by KHSRogue.

Hint: Fooling the solar sensor:
Put the sensor in front of a black light. It will respond with almost full, if not full, solar energy.
Information in this section was contributed by ezc12.

Hint: Different Otenko forms:
If you fire a Rising Sun grenade while Otenko is following you, he will grow very large. .If you shoot him with a Sol Lens, he will glow red. If you shoot him with a Flame or Frost Lens, he will glow white.
Information in this section was contributed by diablo1134.