The single player is actually damn good. Its more of a "classic" style Bomberman (no crazy levels like Saturn/Mega), but its still one of the better single player Bomberman experiences. There are 10 areas each with their own "theme". Each area has 9 levels, a bonus stage, and a boss fight. Sadly, it seems that later on in the game they just start recycling bosses though...
There is a boss from Mega Bomberman in the game though. Which I thought was pretty damn cool. (Sadly, it isn't the giant banana/monkey).
The power-up system works like this:
You pick up power-ups and they get added to your inventory. Via your touch screen you can activate your powerups. Right now I think I have 90 something Bomb Ups, 70 something Speed Ups, and 99 Fire Ups (the max you can have). At any point you can use the touch screen to activate your power ups, and they don't all vanish when you die! There are also 18 other power ups, but they only last during the level you activate them in.
Also, you can't activate any power ups during a boss fight since boss fights take up two screens. So you have to prepare before the start of the level.
In multiplayer, power ups work as they normally would.