You should really play Boktai 1 & 2 on GBA. They are Hideo Kojima games and very very good, pushed the GBA hardware alot. I played through them both, 3 was (J) only.
They focus on Django who can use the power of the Sun and must do so to defeat vampires. They even have a slight metal gear feature of sneak/wall tap etc. I'd put them on par with golden sun/metroid/castlevania etc. but because of the weird name they didn't do too well outside of Japan.
This game looks like a futuristic leap for the series and even uses some of the same sprites, fonts, menus etc from the GBA games. I hope missing out on Boktai 3 doesn't effect this story.
Anyone who disagrees is a lemon.
Thanks a lot Thug. Nice summary. I'll be sure to check them/it out!