Shin Bokura no Taiyou: Gyakushuu no Sabata English translation
新・ボクらの太陽 逆襲のサバタ · Boktai 3: Sabata's Counterattack
The long-standing English patch for the Japan-only third Boktai: the whole script is in English and the game can be finished, with only a few graphics left in Japanese.
What's translated
All of the game's dialogue and menus are in English, so Boktai 3 can be played from beginning to end. The team calls it unfinished only because a handful of graphics were never redrawn; none of them get in the way of completing the game. The project's source code was later published on GitHub.
The solar sensor
The cartridge reads real sunlight, which emulators and flash carts can't provide. Players usually pair the translation with a separate solar sensor patch that lets the light level be set from the controller.
Playing it
Apply the patch to your own copy of the Japanese cartridge, following the notes on the patch's page. Hacking, graphics and tools by Spikeman, script translation and the dumping and insertion tools by DarthNemesis, editing by LordHuffnPuff.