Story

A hostile race of aliens have invaded the planet Earth. A lone soldier takes up arms to fight against the invaders and drive them away.

Gameplay

The game is an arcade-style rail shooter where players shoot from a first-person perspective. Similar to T2: The Arcade Game, players are equipped with continuously firing machine guns rather than pistols as in most light gun games.

The game supports play using a Control Pad, Sega Menacer, or Sega Mouse. Using a control pad, the D-Pad moves the targeting crosshair and 'A' fires. Players can use grenades, which are also aimed at the location of the crosshair, with 'B'. Using a Menacer, the trigger fires and the top button throws grenades. The machine gun has limited ammunition, which goes down slowly as the gun is fired. When it runs out of ammo, it continues to fire but more slowly. Additional ammo and grenades fall down the screen occasionally and can be collected by shooting them. Grenades are also limited in supply, and there are multiple types of grenades with different effects. Collecting another grenade item adds another "stack" of grenades with its own counter, with previous stacks of grenades kept in reserve.

Each stage presents wave of enemies, and after a sufficient number of enemies have been eliminated, the players proceed to the next area. At the end of the stage, the players must destroy a boss to move on to the next stage. Bosses have a numeric health meter. They are large and have multiple vulnerable parts, with different parts being targetable at different phases.

Players have five hearts to represent their health. Hearts shrink three times before they are lost as the player takes damage from enemies. If the player runs out of hearts, the player is defeated and can only continue playing at the cost of a credit.

The game supports two-player simultaneous play, with both players using control pads or with one player using the Menacer and the other player using a control pad. Players share credits. There are three difficulty levels (Easy, Normal, and Hard).