Robo Warrior/Gameplay

Controls

 * : Use the direction pad to guide the ZED through each period. The ZED can move in all four cardinal directions, but cannot move in diagonal directions.  It is also used to move the cursor between items on the inventory screen.
 * : Press the A button to fire your main gun, and to use an item that you have selected from the inventory screen. It is also used to select the item that the cursor is next to on the inventory screen.
 * : Press the B button to plant a bomb at your feet. The ZED will immediately repel backwards upon placing a bomb down.  It is also used to cancel out from the inventory screen.
 * : Press the Start button to begin a new game, or to pause the action mid-game.
 * : Press the Select button to pause the game and bring up the inventory screen.

Player
You control the ZED (Z-type Earth Defense) cyborg as you explore the surface of the planet Altile. Your mission is to find your way through 8 different sections of the planet, which are subdivided into 27 distinct periods. In some cases, you will be required to battle fierce monsters, but in most cases, you will simply need to explore a region and locate the key that leads to your escape and eventual progression through the planet. You are armed with two weapons; a main gun with unlimited ammo, and a finite supply of bombs. The gun is a weak weapon which can be used to attack surrounding life forms.

The bomb is a much more powerful weapon which can be used to destroy certain types of terrain and other enemies, provided they are within the blast range when the bomb explodes. The ZED can also get caught in the blast, and will take a substantial amount of damage, so it is wise to avoid the blast at all costs. When the ZED plants a bomb, it is immediately repelled back one space in order to help you escape. The bombs (shown right) explode in a short period of time, and have a blast radius of one square. Terrain caught in the diagonals of the blast are only half destroyed.

The ZED can gain access to some other powerful weapons by collecting item tiles. The ZED has an energy meter, which allows it to sustain a good amount of damage an still remain active. Losing all of your energy or standing in water for an extended period of time without proper protection will cause the ZED to deactivate, and your game will be over. You are then given the opportunity to start over from the start of the period you died in.

Status
The status bar at the top of the screen shows three details. These details include the score, the amount of bombs in your possession, and the amount of energy remaining.
 * Score: Your score is not just for bragging rights, it is actually a tally of experience as well. When certain scores are reached, the ZED will increase in level.  This level is never shown or indicated, but higher levels improve the ZED's power, speed, and defensive ability.
 * Bombs: The ZED is capable of holding up to 99 bombs at one time. Attempting to collect more bombs beyond 99 will result in no gain.
 * Energy: Last, but not least, you can see the ZED's energy meter, which is capable of charging up several reserve batteries. When one battery is depleted, the next available battery will take its place and recharge the meter.  Getting hit by an enemy, an enemy's bullet, or a bomb blast will cause the energy meter to go down.  Collecting energy batteries, or using the Extra Energy item from your inventory will recharge the meter.

Levels
This table indicates what score you need to achieve each level. At the first level, you possess 100,000 defense points at full energy. Each battery holds 20% of your energy which means they hold 20,000 points each at level 1. Each level increases the storage of each battery by 5,000 points, and the ZED's energy by 25,000 in total.

In Bomber King, getting caught in a bomb blast will cause 100,000 points of damage, which means you will instantly die if you are still Level 1. You only have a chance of surviving if you are Level 2 or above. However, in Robo Warrior, the damage of the bomb blast as been reduced to 40,000 points, making them far easier to survive.

Difference between versions

 * Game is called "Robo Warrior" in USA and Europe and "Bomber King" in Japan.
 * In Japanese version, when you die, you continue from the first stage in a period (example: if you die in period 5-2 you go back to 5-1). In USA version you always continue from the period or boss you died from.
 * In Japanese version your bomb deals more damage to you. It kills you instantly if you have defense level 1. In USA version bomb only takes 2 life bars at defense level 1 (you start with 4 lifebars).
 * Opponent's nail shot deals more damage in Japanese version.
 * Water raft lasts twice longer in USA version (34 seconds).
 * Score points are shown as stars in USA version while it's shown as kanji in Japanese version.
 * Shield item is shown as shield in USA version while it's shown as kanji in Japanese version. The Japanese version shows the character 超, or chou, which means "super" or "hyper".
 * European version runs slower, but you walk slightly faster and items last longer. Sound is noticeably slower.