While it seems like an amazing idea to have 100-man Bomberman battles, this game has one major downside: 99 of those people are computer controlled. So you'll need to get your massive multiplayer online Bomberman action somewhere else.
The app also contains normal Bomberman matches in addition to hundred man ones and claims a total of over 200 stages. Also, as you play, you level up and can increase your starting stats such as speed, amount of bombs and length of fire.
I personally found the 100-person battles (and even the normal ones) a bit hard to control on my tiny little iPhone screen. Worse yet, my poor iPhone 3GS kept crashing midway through the first 100-man battle.
So while it may not be exactly what you hoped for from the title, there's really no reason not to try it for yourself as 100-Person Battle Bomberman can be downloaded free from iTunes and Google Play (though you will need a Japanese account it seems). So what are you waiting for—try it yourself!