Game Boktai : The Sun is in Your Hand

Boktai: The Sun Is in Your Hand is the first Game Boy Advance game that uses sunlight to influence gameplay. In the game, you'll follow the adventures of Django, a young vampire hunter on a quest to rid the world of evil. As Django, you must overcome traps, defeat enemies, and fight through the deepest parts of dungeons. Watch out for the amount of sunlight--Django is stronger by day, while the vampires are stronger by night. The game features a solar sensor on the cartridge and a real-time clock system.