Er...Yah. Ever seen the Bomberman64 title screen? Ever wondered what that weird Japanese Kanji symbol at the atart of the logo was? Somebody couldn't be bothered fixing up the title screen for international release...
It's "Baku", In Japan, Bomberman64 was named BakuBomberman, and The Second Attack! was BakuBomberman2 I believe. That's just name changes.
To answer your question there were 4 Bomberman games for the Nintendo64...