- Joystick or Direction Pad: Use the joystick or direction pad to pilot the Vic Viper or the Lord British in any one of eight directions. Although the screen scrolls automatically (forward on the odd stages, upward on the even stages), you can travel to any visible portion of the screen. However, you cannot collide with any part of the terrain, so you must steer clear of any obstacles that occupy your path.
- Fire: Press the fire button to shoot your primary weapon, which is either regular shots, ripple lasers, or laser beams. Holding the button down allows you to fire continuously, although it's possible to fire more rapidly than holding the button down ordinarily allows. Holding the button down with laser beams allows you to fire the longest possible uninterrupted beam.
- Missiles: Press the missile button to launch missiles to either side of you if you have collected the Missile power-up.
- Power-Up: Only present in the Japanese version of Lifeforce, press the power-up button when you would like to activate whichever selection is highlighted in the power-up bar at the bottom of the screen (see below). You can only use the Power-Up button when a selection is highlighted, and the words are present in the selection.
- Start: Press the start button to begin a game. On consoles, press the Start button while the game is proceeding to pause the action.
Player 1 is the pilot of the blue Vic Viper, while player 2 is the pilot of the red Lord British. The Vic Viper has been slightly upgraded from it's previous battle in Gradius. The Double weapon has been replaced by the expanding Ripple Laser, and the original Laser has been upgraded to what is known as the Cyclone Laser. The Lord British was developed using the Vic Viper as the basis for its designs, and is fully compatible with all of the same weapons modules.
You must fly the Vic Viper and the Lord British through six stages in an effort to defeat their leader and save your home. Both ships are extremely maneuverable and powerful, but they do not start out this way. As certain enemies are defeated, they will leave technology and energy which can be collected by the ships and utilized to activate additional weapons and functions. When either ship is launched, it starts the mission out at the slowest speed with only the most basic weaponry. You must collect the abandoned weapon modules in order to build up the destructive power of the Vic Viper and steadily increase your offensive abilities.
In Salamander, different enemies will leave modules behind when defeated. To activate a weapon or ability, simply collect the module.
Speed Up naturally increases the speed at which you may maneuver your ship across the screen. The more Speed Ups you apply to a craft, the faster it can fly around obstacles and enemies, or line up with oncoming enemy crafts. The Speed Up power-up can be selected five times before it maxes out. However, you should not collect this power-up to that extent. Doing so will cause a condition known as "over control," which occurs when the ship moves too quickly for you to make meaningful adjustments to its position in space. Every player has a speed at which they are most comfortable guiding the ship through obstacles. Do not select a faster speed than you are comfortable handling.
If you activate the missile power-up, your ship (and every Option that follows it) will launch two missiles. If the screen is scrolling horizontally, the missiles will launch upward and downward, while if the screen is scrolling vertically, the missiles will launch left and right. The missiles continue to travel until they fly off the screen, or until they land on the surface of some terrain. They will continue to coast along the terrain as long as the terrain is flat or slopes downhill. They will explode if they come into contact with an enemy, doing enough damage to destroy most basic enemies. Two sets of missiles can exist on the screen at one time.
Since the ship's missile systems now fire in two directions, the Double weapon technology has been replaced with the Ripple Lasers. The ripple Laser fires an energy ring that streaks from one end of the screen to the other. As it travels along, it actually expands and grows, making it far easier to hit enemies at a distance than those flying up close to the ship. The Ripple Lasers cannot be activated simultaneously with the regular Lasers.
The original thin laser beam has been upgraded with the cyclone laser, a laser which has a much thicker beam, but travels across the screen slightly slower. The beam can extend beyond the distance of the screen simply by holding the fire button down. The beam will travel up and down with the height of its originator, even after the beam terminates and flies forward on its own. The beam will strike any enemy that it hits, usually destroying any basic enemy that it comes in contact with. The cyclone laser does not suffer from the deficiencies of the earlier laser system, where parts of the laser would not register a collision with the enemy. As mentioned above, you cannot activate the Ripple and the Laser at the same time.
By collecting an option, you essentially multiply the fire power of your ship. If your ship powers up, so do any of the Options. Options are primarily used to increase your offensive power, but they can also be used to safely destroy objects in positions that the ships cannot survive. The Options typically follow your ship in a snake like way, trailing behind in the ship's previous positions. Small adjustments to the ship's position causes the options to similarly adjust themselves. Between both players, you can only activate up to a maximum of four Options. That means if one player has three options, the other player may only have one. The enemies attack you with a firepower that is proportional to your perceived threat. Therefore, the more Options you have activated, the more aggressively the enemies will attack you.
Collect a Force Field to attach a shield to the nose of your ship. They can absorb a large number of enemy bullets and collision. Each time they absorb damage, they get a little smaller. Eventually, they will disappear entirely, indicating that the benefits of the shield have ended. The shield is most effective at blocking attacks from the front of the ship. However, if you manage to collect a second force field before the first runs out, it will appear above your ship, or on the left. If you manage to get a third, it will appear below your ship, or to the right.
Japanese Lifeforce power ups
The Japanese version of Lifeforce returns to the original power-up system found in Gradius. Rather than receiving the benefits of a weapon immediately, each player must instead catch power capsules, which highlights a bar on the power-up meter. Each capsule moves the highlighted bar over one until it wraps around to the beginning. The player must press the Power Up button when the desired power-up is highlighted and available.
Unique to Lifeforce is the fact that the Vic Viper and the Lord British possess different power-up arrangements. Both players' meters are shown below. The blue meter on the left belongs to the first player's Vic Viper while the red meter on the right belongs to the second player piloted Lord British. The Vic Viper's meter is arranged in the same manner as it was for Gradius. The Lord British meter is arranged in such a way that makes it very easy to achieve a high level of fire power very quickly, but much harder to achieve a useful level of speed.
This is the power-up capsules which is left behind by different types of enemies. One type of enemy that leaves power-up capsules are formation enemies; enemies that come out in large groups or chains. If every enemy in the formation must be defeated, the last enemy defeated will leave a power-up capsule behind. The other type of enemy that provides power-up capsules are alternatively red colored enemies. Most enemies have a standard color, usually some variant of gray or blue. However, when an enemy is predominantly colored red, that is an indication that the enemy will leave a capsule behind when destroyed.
Unlike in Gradius, there are no Crash capsules in either Lifeforce or Salamander, which clear the entire screen of enemies.
Choosing which power-ups to take, and in what order, is an essential part of the strategy when playing Lifeforce. Choosing the best selection depends on your playing style and the stage that you are about to encounter.
- When starting off with no power-ups, it's a good idea to start with one Speed-Up. This allows you to fly quickly between the different heights that power-up capsule providing enemy formations will appear at, but it's not necessary if your timing is very tight.
- Opting to activate the laser right away can cut down on the amount that you need to fire, or even how fast you need to arrive somewhere, in order to destroy an entire formation and collect a power-up capsule.
- Activating at least one Option early on can also significantly enhance your firepower during the pre-stage portion of battle.
- Selecting missiles is important once you arrive at the terrain portions of a stage, and may be put off until that time, although you may find it useful to destroy high and low enemies during the pre-stage as well.
In general, you should aim to have one Speed-Up, one Option, Lasers and Missiles by the time the pre-stage portion of the stage is complete, which is 12 capsules altogether for the Vic Viper, and 11 for the Lord British (five of which is needed for the speed up). If you are prone to getting hit by enemy bullets frequently, you may wish to substitute the lasers with a shield, although this will cut down on your offensive capabilities until you can amass the four capsules needed for lasers.