Dark Lens
Successfully complete the game to unlock the Dark Lens.
Dark Frame
Successfully complete the game two times to unlock the Dark Frame.
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.
Dark Gun
Combine the Dark Lens, Dark Frame, and Dark Battery.
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.
Hints
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.
Defeating Boks
Use a Spear Frame. It will either stun them for awhile or kill them.
Defeating the Volcano Area Immortal
First, take out the Permafrost Immortal. Although this is not easy, it will make the journey easier.
Fooling the solar sensor
Put the sensor in front of a black light. It will respond with almost full, if not full, solar energy.
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.