Continuous explosions
Equip either the Invincibility power-up or the Fire Suit. It is best to equip some Speed-Ups, Bomb-Ups, and Flame-Ups for the trick to be more effective. Plant a bomb and stand next to it, waiting for it to explode. Meanwhile, repeatedly tap A to plant a second bomb in the blast, then another, and so on. The process can continue for as long as desired. Having the Bomb-Ups simply means the chance of failure is reduced, while the Flame-Ups and speed-Ups allow you to cover more ground during the time you are invincible to the bomb blasts.
General items
Bomb Up: Increases amount of bombs that can be dropped by one (maximum of eight).
Fire Up: Increases firepower of bombs by one level (maximum of eight).
Full Fire: Increases firepower to maximum automatically (maximum of eight).
Speed Up: Increases speed by one level (maximum of eight).
Multi-player or Battle mode items
Bomb Down: Decreases the number of bombs able to drop (but will not reach zero).
Fire Down: Decreases firepower by one level (but will not reach zero).
Rubber Bomb: A bomb that can bounce when punched or kicked.
Skull: Causes a state of illness or a black fog around your player that lasts for one minute. However, if you touch another player the illness will become their problem. Symptoms include speed minimization or lowest speed, will not be able to place a bomb, bombs will drop unexpectedly, and freezing.
Speed Down: Decreases speed by one level (but will not reach zero).
Question Mark: Randomly picks a function of another item.
Single stage items
The following items only last for a single stage of battle; pay attention to the upgrade's button selection.
1 Up: Another life; cannot be stocked.
Heart: Lets Bomberman get out of one blunder such as a bomb blast or enemy contact.
Invincible: A Bomberman upgrade allowing him to be resistant to all forms of attack including bomb and enemy that lasts only for a certain amount of time.
Fire Suit: A Bomberman upgrade allowing him to be resistant to bomb blasts only.
Clock: Adds an additional minute to the time.
Dangerous Bombs: A bomb upgrade that allows the first bomb to explode in a square radius.
Land Mine Bombs: A bomb upgrade that hides a dropped bomb as a little yellow dot until activated by enemy or yourself.
Pass Through Bombs: A bomb upgrade that allows the flame to penetrate more than one soft or destroy-able block.
Power Bombs: A bomb upgrade that maximizes the first bomb instead of spreading out the power through each bomb.
Remote Bomb: A bomb upgrade that allows you to use B to detonate dropped bombs manually.
Bomb Kick: A Bomberman upgrade allowing him to kick a bomb and stop it with X.
Bomb Punch: A Bomberman upgrade allowing him to blow away a bomb in your way with Y.
Line bomb : A bomb upgrade allowing for you to drop all the bombs you have at once using Y.
Power Glove: A Bomberman upgrade allowing him to pick up and throw dropped bombs.
Shield: A Bomberman upgrade allowing you to shield him from a bomb blast for several seconds.
Glasses: A Bomberman upgrade allowing you to view the exit and all items in a stage.
Metawall: A Bomberman upgrade allowing you to walk through soft blocks for certain amount of time.
Metabomb: A Bomberman upgrade allowing you to walk through bombs for a certain amount of time.
Walk in place in multi-player mode
While playing a game in multi-player mode, hold R, move slightly, then stop. If you are still holding R, your character will walk in place.