This game is one of the legendary Japan-only GB games. In fact, groups of rom-hackers are still trying to remake it in a more up-to-date system, or at least translate to English the original ROM.
Why is this game so "legendary"? Well, the main reason is that this game was used by Nintendo as the ROM base for the GB/GBC Zelda games, Link's Awakening and both Oracles. As you can see in the image, we already have an air vision, a status bar in the bottom part with hearts and items, and a graphic style that already looks similar to that of LA. Plus, one of the main characters, Richard, was reused in both LA and Oracle of Ages, in the first as, well, Richard (with his frogs, part of the main storyline of this game), and in the second as Ralph, Nayru's love.
This game is also known because Kazumi Totaka, "Totakeke", composed its soundtrack, thus including the most famous videogame easter egg ever, Totaka's Song:
http://youtube.com/watch?v=EfXSa0m_ryc
The title of the game is a corruption of Hemingway's book, "For whom the bells toll?", being translated to "For frogs the bells toll", since the main character needs to turn into various animals, specially a frog, for most of the adventure.
The japanese name, the one which actually matters here, is "Kaeru no Tame ni Kane wa Naru"
