Tangent.

A deterministic game of vector approach combat.

(It's a WarGame. With no randomiser of any sort.)

Visualisation:

Fighters are entering the atmosphere, approaching the planet along a tightly guarded coridoor. Elite fighters scramble to block this gap in the defences...

Start with a hex map. Designate one player as the defender. His end of the map is the planet. Exiting at this end results in the destruction of a craft. The other player is the attacker, and he is approaching from space. The map is assumed to be infinite in the other two directions.

Each player should have the same number of ships - and not more than three.

Each ship has:

• A number of remaining shields (starts at 100)
• A current speed.
• A position on the grid.
• A facing.
• A thrust rating.
• Some number of weapons. (Up to one 'engaged')
• A chosen target.
• A tangent count.
• A loss count.

Turn order:

1. Player 1 ship 1
2. Player 2 ship 1
3. Player 1 ship 2
4. Player 2 ship 2
5. etc.

On the first turn, to make up for the advantage of moving second - the defending player places his first ship. The attacking player then places his first ship and moves it as normal. The defender then takes his first move, and places his second ship.
Defender ships start with zero speed, and may choose their facing.
Attacker ships start with any speed up to their thrust, and face towards the planet.

Movement. (Phases in order)

1. The ship can change its speed up or down (the maximum amount depends upon the ship stats)
   Note: A ship may not stop moving. Doing so means instant destruction. (The setting justifies this - but it's primarily a means of ensuring the tempo race can't stall)
2. The ship then moves forwards a number of places equal to it's current speed.
   note: These two steps can be executed more simply as followed. "I'm speed 5 right now, and thrust 2. So I can move forward between 3 and 7 hexes."
3. Having moved, the ship may then turn one hex facing left or right.
   Note: A 'turn' of play equates to a single 'turn' of a facing. This is neat.
4. Then weapons fire happens.

Firing. (Phases in order)

1. If you do not currently have a weapon engaged, you may choose a weapon and engage it.
2. You may choose to disengage your weapon. (With one exception, the lance) (Clear loss, clear tangent, disengage weapon.)
3. If your chosen target is inside acquisition range, and in the acquisition arc of your current weapon, acquire a tangent.
4. If it is not, then your weapon starts to lose lock. (Count up on 'loss') If you've been lost too long then the weapon is disengaged. (Clear loss, clear tangent, disengage weapon.)
5. If you have enough tangents then as long as the target is within firing range and firing arc the weapon may fire. (You may choose to hold off without penalty - which may be advantageous for missiles)
6. If it's a direct-fire weapon, the appropriate amount of damage is done to your targets shields (possibly removing it from the game)
7. If it is a missile type, then it launches - becoming a second craft which moves when its parent ship does.
8. After firing (either type) the weapon is diengaged (Clear loss, clear tangent, disengage weapon.)

Note: Deliberately, if you lose tangent with a weapon you may not immediately gain tangents with a new one - at least one turn is spent not acquiring tangents.

Missiles.

Start moving with a speed equal to their parent craft plus some offset. Each turn they turn directly towards their chosen target (if equidistant between two faces, you may choose which) Each turn they reduce their speed by one (becoming destroyed if they stop moving)
If they end up in the same hex as their target, they deal their damage to the shields (possibly destroying them).
The missile is then destroyed.
They may be taregtted by weapons like any other craft. They have 1 shield - any damage at all will destroy them.

And I can't find the stats for the craft and weapons.
In general, though - weapons which fire rapidly (needing only 2 or 3 tangents) do little damage. The only weapon which destroys in one shot has a 'straight line' arc for its firing (though an easier one for tangent acquisition) and needed a long lock on.

The only 360-arc weapon had a very (2 hex?) short firing range, and the special ability that it fired when it had collected its tangents whether you liked it or not once engaged, and it would damage ALL craft in range, including the firing craft.

Since moving 'second' is the only way to guarantee a good shot, you want to slow down and force the opponent to move. But moving too slowly means they can easily keep you in their sights and you risk having to stop and explode. So keeping tempo is important - by choosing your weapons carefully and using your fighters together carefully to intefere with their plans.
It is quite useful, for example, if the opponent is about to (say) fire a light missile at one ship, to start acquiring superheavy laser lock with your second ship. Sure, they could keep locking on - but then they WILL lose their ship. So they have to break off.