Also known as: Bomber King (JP)
This game has regional differences.
Robo Warrior is kinda like a souped-up Bomberman, from the same company. A sequel was released for the Game Boy, which was localized as a Blaster Master Boy.
An odd mode accessible from the title screen where you can listen to the main theme song and view the lyrics on the screen. The Japanese version unlocks this after you enter the Item Shop upon clearing Levels 1, 3, 6, 9, 12, 16, and 21; just die and return to the title screen.
While it remains in the US version, it can only be enabled by setting RAM address $02F8 to 01 before the title screen appears. The option will appear immediately, and can be selected... but as most of the kanji CHR data is missing, you can't see the text.