Robowarrior (Bomber King in Japan) is an action game released for the NES in 1987 in Japan and later published by Jaleco for the US in 1988 with some minor changes. It is a side-scrolling, top-down action game that requires that the player clear out large areas by placing bombs and removing obstacles. Players take control of a Z-type Earth Defense android as he tries to defeat the alien emperor Xur. The player has two main attacks, a rifle that shot short range bullets, and bombs.
Robowarrior features two different types of levels, both of them requiring the player to perform a specific action in order to move on. The first kind of level is a traditional point A to point B layout with a key somewhere on the last screen that needs to be found to move on. The other kind of level is an infinite loop that the player would continue to cycle through until they found the chalice, and then the exit would appear at the end.
A to B stages are arguably easier as there is a set ending, but the key can be hidden anywhere, including areas of the stage that aren't traditionally destructible like walls. The player is required to bomb everything and anything on the screen in the hope of finding the key. When trying to blow up a part of the environment that wouldn't typically blow up, multiple bombs are needed. The player has a limited number of bombs to accomplish the task. Once out, enemies have to be shot in order to pick up more, one at a time.
Many stages feature water, which slows the Robowarrior and causes him to slowly sink to the bottom. After a few seconds he will sink completely, which costs a life. In early stages, water can be avoided easily, but later stages are almost entirely water. The player can use life preservers to stay afloat during these levels, but if they take too long their supply will run out and they will drown.
Enemies re-spawn constantly in every level, giving the player a much needed, although extremely inconvenient source of bombs. Enemies have many advantages over the player. While many of them die with only one hit, most enemies are faster than the player, many can hover over the environments, and others can shoot over them as well. While the player's bullets stop at every wall, the enemy's can travel over every barrier across the entire screen.
Dispersed throughout the levels are bosses that the player has to defeat. These bosses don't follow any of gameplay involved in the stages and have no tiles in need of bombing. They are more traditional dodge and shoot affairs and like all the other enemies tend to be much stronger and faster than the player.
Adding to the games extreme difficulty are two additional factors: First, the player's health doubles as power for the Robowarrior, meaning that it depletes constantly over time. Take too long and it will run out, which means losing a life. If the player dies, they may continue on the stage that they died on, but they lose half of their items and half the range of their gun.
Throughout the game, the player can pick up or purchase additional items to assist their mission. These items require the player to open the menu and select them before their effects can be appreciated. Each of these is a one-use item that the player can stockpile and use when they see fit. These include:
- Candle - In darkened stages, lights a small amount of the stage around the player. Lasts for a short time.
- Energy Tank - Completely replenishes one battery meter.
- Stopwatch - Freezes all enemies for a short time.
- Super Boots - Allows the player to move twice as fast for a short time.
- Missile - A much more powerful shot that will destroy all enemies and items in its path, but will stop at walls.
- Flash - Instantly destroys all enemies on screen, does not affect tiles.
- Cross Fire - Makes bullets fire in all directions.
- Life Preserver - Allows the player to float on water for a short time.
- Lantern - In darkened stages, lights the entire screen for a short time.
- Mega Bomb - Clears the entire screen, destroying all enemies and tiles that are visible.
In addition, the player can pick up other items that are used instantly. Health and money pickups are dropped by enemies and are in blocks. Bomb icons give the player an instant upgrade of ten additional bombs. Power blocks allows the player's rifle to shoot one additional space for each pick up. A shield will make the player invincible for a few seconds and star blocks will add to the score. Finally, there is the Hudson Bee, which will randomly add to the player's stock of items.