Bomber Mansion
Start a new game as bomberman, then kill yourself with bombs. The Prof will say you need more time at Bomber Mansion. When it asks you to continue, select no and go to the main menu.
Bonus multi-player battle mode characters
Hige Bandit 2: Get all three Red Hige Hige Cards
Hige Bandit 3: Get all three Blue Hige Hige Cards
Hige Bandit 4: Get all three Green Hige Hige Cards
Mujoe: Get all three Yellow Hige Hige Cards
Mighty: Get all five Jetters Cards
Instruction manual
Under the explanation of all the bomb items, it shows a picture of the light bulb but gives the description of the jug.Just next to it, the manual shows a picture of the jug with the description of the light bulb.
Planet Bomber World
Get all ten Lightning Cards from the evil bombers, then defeat the Boss in level 5-4 (Warhorse). The Planet Bomber world will now be unlocked. In it, you will battle two new Bosses (Mujoe and Dr. Mechadoc).
Alternate ending...