Battlezone and Tank Movement

Of all of the innovations in the 1980 arcade hit, Battlezone, the one that will likely stick out the most to a modern gamer is the control scheme.  Much like Crazy Climber, the game challenges you to control the limbs that direct movement rather than movement itself; only in this case, instead of controlling arms, you're controlling a pair of tracks.

In this entry, I'll demonstrate how you use the tracks to control your tank's movement, including an explanation of the physical rationale behind it.  Finally, I'll talk about how you can use those controls to be a successful Battlezone tank operator.

Tank Movement

Game Controller

In my Battlezone excursions, I used a standard gamepad with a track mapped to each joystick and the fire command mapped to the right trigger.  Since you'll need a thumb for each joystick, you'll want the firing mechanism to be somewhere other than the front face of the gamepad.

The joysticks only issues commands in two directions of motion, so you could map the gamepad joysticks to a two-way scheme like this:

This is represented in the joystick map parameter as "8888...5555".  You may not find it necessary to fiddle with the joystick map, however -- I found the standard 8-way joystick to work just fine.

Forward/Backward

Moving forward and backward in your virtual tank is just a matter of pushing both joysticks up (forward) or both down (backward).  

Hopefully, this is easy to understand when you think about what the controls are doing.  Pushing the joysticks in the same direction means the tracks are moving in the same direction, driving you forward or backward.  Dual-track motion will maximize your speed, minimizing the chances that your tank is hit by enemy fire.

Turns

What happens if you move just one track?  Well, this is where things might get a little less intuitive.  Since the tracks are located on either side of your tank's center of mass, driving them does more than just propel you forward or backward.  They also apply a torque; that is, a force that tends to rotate the tank.

This rotational force, combined with the forward/backward motion induced by the track, will cause the tank to trace out part of a circle. The reason you don't get any rotation when the tracks are moving in the same direction is that the rotational forces from each track are in opposite directions and cancel each other out.

If you need to turn quickly, then you'll want both tracks torquing in the same direction, like so:

It's much like spinning a coin on the surface of a table -- you push opposite sides of the coin in opposite direction to maximize the spin.  But be careful, because a pure rotation means that your tank isn't moving forward or backward, and is a sitting duck to enemy fire!

Navigating Battlezone

Regular Tanks

When you first start Battlezone, you'll be faced with an enemy tank somewhere near the center of your field-of-view.  Watch for spots to appear on your radar on the top of the screen -- that will indicate where the tanks are relative to your current position and viewing direction.  Early on, the tanks will appear in front of you, so you won't have to turn much to target them.  What's more, they start in a wandering mode and won't pose an immediate threat to you.  Take this chance to get warmed up with the motions I described above, because it won't be long before things get hairy.

After knocking off a few tanks, they'll start appearing off to the sides or behind you.  This is a dangerous situation to be in because they can start firing on you before you can even turn to face them.  I found that I couldn't count on being able to get off the first shot if the tank was more than about 45 degrees from my initial firing line.  So what do you do?

Well, I found two workable options.  The hard way is to be brave; that is, throw your tank in full reverse (both joysticks back) and try to line up a shot on your opponent between their own shots.  This is risky and difficult.  Instead, I recommend the coward's way out -- run!  As soon as a tank appears off to the side or behind you, throw your tank into full forward motion.  In most cases, you'll be out of range before the enemy tank exits wandering mode.  As a side benefit, this allows you to explore the surrounding terrain and pick off any nearby UFOs for bonus points.

Missiles

While tank battles can drag on for a good while, missiles only give you one or two shots at them before it's too late.  You can throw the tank in full reverse to give yourself a little more time to judge the missile's trajectory, but be careful not to fire too soon.  Note that the missile will sometimes veer off to the side at the last minute, so you might need to make quick rotational corrections.  Hitting a missile at close range doesn't require pinpoint accuracy, so use the two-stick rotation to maximize your rotation speed before firing.

As the game progresses, the missiles do an increasing amount of juking and jiving, until it gets to the point where the player has to guess which way the missile is going to swerve at the last second.  It reminds me of the guessing game that goalkeepers have to do in soccer penalty kicks, except in this case, the goalie doesn't want to get hit by the ball.

Super Tanks

Super tanks are incredibly difficult enemies to handle, particularly if they appear behind you.  They move so quickly that they will sometimes roll right into you before you can turn to face them.  So you can forget about running away.  If they do appear in front of you a sufficient distance away, you can use the same dog-fighting techniques you would use on an ordinary tank; that is, moving backwards at an oblique angle from the enemy and then sneaking a shot in between enemy shots.

Barriers

Finally, a quick note on Battlezone's barriers.  The cuboids and tetrahedrons that litter the landscape can double as cover, if you're sly enough.

The enemy AI is not particularly clever about these barriers, so if you can successfully navigate your tank behind one, the enemy will eventually just drive out into your line of fire.  Be careful of barriers at close range, however, as your tank is quite wide and can very easily get stuck at the edges.