Tactical Combat in GURPS 4.0
For the sake of simplicity I reduced this to two rounds of a single fighter massively outnumbered by undead. The fighter figurine actually has a a mace not a sword so do not be fooled hehe. The undead are a Standard unarmed Zombie, a Skeleton with a shield and a spear and 5 bone hounds. (They have long necks increasing their bite range to 1 rather then C. They can also howl to force a fright check but in this example they just bite.)

Fighter chooses to WAIT until something moves into range and then I will attack them.

A bone hound STEPS and Attack. This is interrupted by the fighters wait maneuver. The fighter hits the torso for 6 crushing. (The bone hound failed to dodge) These Bone hounds are wearing leather armor and have a natural DR of 2 totaling 4. 2 points of crushing damage penetrates the DR and gets doubled to 4. (Skeletons take double damage vrs crushing). The beast now gets his attack. Being undead he does not suffer any kind of shock penalty etc. He rolls and hits, the fighter chooses to block and succeeds.

The Zombie MOVES into close combat (Occupies the same hex) and attacks. Having a 12 skill to punch is reduced to 8 for moving and attack. He attempts to punch the fighter. The fighter decides to RETREAT and dodge and steps back 1 hex. Retreating adds 3 to his dodge and he easily succeeds. (QUESTION: Does his shield HELP him in this situation? Its close combat but he is RETREATING a hex. Answer: 1. Yes, you get the shield bonus if you retreat out of close combat.)

Another Bone hound Steps and attacks. The fighter attempts to dodge, he does not get his shield bonus on this side. (QUESTION: Does he get his RETREAT bonus vrs this Hound or only versus the zombie? Or only versus his FRONT hexes? Answer: 2. The retreat bonus counts against ALL attacks from the ONE opponent you actually retreat from. So Zombie Only!) In any event he dodges.

Another Bone hound Moves and Attacks the rear with a bite. Having a 15 skills reduces his attack to 11 but move and attacks are capped at 9. So his skill is 9. He rolls and 8 hitting. The bite of a bone hound deals 1D+3 and has an armor divisor of 2. The fighter cant defend against a rear attack. The hound rolls 6 for damage. The fighters 10 DR is divided by 2 to 5 and the fighter takes 1 point of damage.
(Question: The hound was behind the fighter but started within his peripheral vision... Is this considered a run around attack? Answer 3. I believe so yes, if you could see your opponent at any time during his move, you should be able to defend as a runaround attack.)

Another hound moves and attack hitting again, the fighter dodges again successfully. (Having a shield on that side helps tremendously.)

Another hound moves and attacks and misses.

Another hound moves and attacks and misses.

A skeleton moves and attacks. (he cant step and attack since he started on higher terrain. Now this is kind of a house rule since the rules say you can ALWAYs move 1 hex.) He pokes the fighter in the back who again cannot defend. The skeleton does 6 points of damage which harmless glances off his back. (However his backpack did take a point of damage)

Yet another hound moves and attacks and misses. (The fighter is now completely surrounded)

Round 2. The fighter declares he is using extra effort to deal an extra point of damage per die. He swings and hits but the zombie dodges. He spends a character point for heroic rolls to change the zombies rolls to critically fail his dodge. His attack normally does 2D+3 (+2 lightning damage and +2 for extra effort) He rolls a 10 and hits for 10+3+2+2 = 17. The zombie is destroyed.

A bone hound steps and attacks. (He HITS!) See below.

The fighter opts to retreat again. But there is no where to go, so he steps into an OCCUPIED hex with his rear facing the front 3 hexes of an opponant. (QUESTION: Can he do this? By the rules I think he can but wondering. Answer: Nope: 4. P391, you can't retreat into an occupied hex. (yes, being surrounded sucks))

This picture could not happen unless he slammed or evaded through or moved into the occupied hex. You can't RETREAT into an occupied hex.
These are Answers from StormCrow42. Full discussion here: http://forums.sjgames.com/showthread.php?t=38005
Bone Hound Combat generator Fun: http://www.whatisthedot.com/GurpsCombatGen.Zip (VERY limited combat gen that attacks and defends every round, some things are configurable, you need .Net Framework to use)
Here is the Bone Hound above in case you want to use them in your campaign.
Name: Bone Hound Race: Skeleton
Attributes [-58]
ST 12 [18] (ST includes -1 from 'Skeleton (Magic)')
DX 12 (DX includes +2 from 'Skeleton (Magic)')
IQ 4 [-80] (IQ includes -2 from 'Skeleton (Magic)')
HT 10
HP 14 [4] Will 4 Per 4 FP 10 Basic Lift 29
Damage 1d+1/2d+1
Basic Speed 6.5 (Basic Speed includes +1 from 'Skeleton (Magic)')
Basic Move 6 Ground Move 6 Water Move 1
Social Background
TL: 3 [0]
Advantages [61]
Combat Reflexes [15] (Long Necked Worg)
Damage Resistance (2) [10*]
Doesn't Breathe [20*]
Doesn't Eat or Drink [10*]
Doesn't Sleep [20*]
Extra Legs (4 Legs) [5*] (Long Necked Worg)
High Pain Threshold [10*]
Immunity (All Mind Control) [30*]
Immunity to Metabolic Hazards [30*]
Indomitable [15*]
Injury Tolerance (No Blood; No Brains; No Eyes; No Vitals; Unliving) [40*]
Sense Living [10*] (Long Necked Worg)
Short Spines [1*] (Long Necked Worg)
Single-Minded [5*]
Striking ST (3) (No Fine Manipulators) [9*] (Long Necked Worg)
Teeth (Sharp Teeth) (Armor Divisor (2)) [2*] (Long Necked Worg)
Temperature Tolerance (10) [10*]
Terror (Howl of the Damned) (2) (Limited Use (1/day)) [24] (Zombie hound)
Unaging [15*]
Unfazeable [15*]
Vacuum Support [5*]
* = item is owned by another, point value is included in the other item.
Disadvantages [-197]
Appearance (Monstrous) (Universal) [-25*]
Cannot Learn [-30*]
Dependency (Mana) (Common) (Constantly) [-50*]
Fragile (Brittle) [-15*]
Fragile (Unnatural) [-50*]
Hidebound [-5*]
Horizontal [-10*]
Incurious (6-) [-10*]
Low Empathy [-20*]
Mute [-25*]
No Fine Manipulators [-30*]
No Sense of Humor [-10*]
No Sense of Smell/Taste [-5*]
Reprogrammable [-10*]
Skinny [-5*]
Slave Mentality [-40*]
Social Stigma (Dead) [-20*]
Unhealing (Total) [-30*]
Vulnerability (Crushing Attacks) (Common) (x2) [-30*]
Wealth (Dead Broke) [-25*]
* = item is owned by another, point value is included in the other item.
Quirks [0]
Cannot Float [-1*]
Sexless [-1*]
* = item is owned by another, point value is included in the other item.
Packages [0]
Automaton [-85*]
Quadruped [-35]
Skeleton (Magic) [-162]
* = item is owned by another, point value is included in the other item.
Skills [11]
Brawling (No Fine Manipulators, +0%) DX/E - DX+3 15 [8]
Jumping DX/E - DX+0 12 [1]
Running HT/A - HT-1 9 [1]
Stealth DX/A - DX-1 11 [1]
Stats [-58] Ads [61] Disads [-197] Quirks [0] Skills [11] = Total [-183]
Armor & Possessions
1 Leather Hound Barding (TOTAL DR: (Counts natural and armor) DR4 Head, Torso and Neck DR 10 Skull) Wgt:3 Location:face, head, neck, skull, torso
Description
Usually appearing in packs of 4-5 these beasts are created by using a variant zombie spell that must be cast on any variety of a Worg corpse. This corpse must be at least 6 months old for the spell to work. The pack will typically howl once or twice upon seeing living humanoids and will then attack anyone that did not flee. The hounds home in on the living using sense living. (They always ignore those they protect when using this ability)
These hounds can be told to protect up to INT+1D4 living creatures. Anyone not protected is hunted. (This includes, dear, rabbits, large insects and the like.) In addition to protecting a limited number of living creatures they can be given up to 2 simple commands. (Patrol the area surrounding my tower, Attack anyone you are able too, howl for help if you can not attack them)
They also can be ordered for many different tactics but if not specified they usually attack the least armored foes first before moving onto the armored ones. (Spikes attack every foe in close combat as a free action)