This page describes known details about the combat in Van Buren, the canceled Fallout 3 by Black Isle Studios. They are largely based on forum discussions of fans with J.E. Sawyer.
Action Points[]
J.E. Sawyer said: "The biggest stumbling block in Fallout TB → RT is movement and AP. So far, the best movement translation seems to be this: high AP characters move faster since, for practical purposes, they do in both TB and RT. A 10 AP character will move 10 hexes in TB over one round while a 6 AP character will move 6 hexes in TB over one round. If that is converted into real-time, the 10 AP character will move 10 hexes in six seconds and the 6 AP character will move 6 hexes in six seconds. That's an analogue.
However, the general tendency in RT combat systems is that movement can't "really" cost anything. When characters move hurky-jerky around the battlefield, stopping to pause for precious APs that they immediately burn, it becomes a little... bizarre. So, what then can be the cost? The best answer I can find is: AP regeneration. A moving character never regenerates AP. He or she can run and run and run all the live-long day at whatever rate is dictated by his or her base AP, but he or she won't gain a single AP back until he or she stops (or perhaps the regeneration rate still exists, but at a pitiful fraction of its total value).
Higher AP characters would still catch up to fleeing characters in less time and either attack or easily re-accumulate APs that will eventually result in an attack into the fleeing character's back. A character who gleefully shoots a submachinegun burst and then runs for the hills will have to stop and wait for a full six seconds to get his or her AP pool back. If two characters with expended AP pools run the same distance, the higher base AP character will arrive at the location first and regenerate the equivalent AP for time saved by the time the slower character arrives.
This is not a perfect analogue, but it's really not horrible, and again, it has no effect on the TB component of the game. People playing using the RT system will find that certain scenarios play out easier, and some scenarios play out with more difficulty. Ultimately, though, it still has more fidelity to TB SPECIAL than any RT D&D game has to TB D&D.
Unarmed[]
If the advantage of firearms is range and damage at the cost of ammo conservation, and the advantage of melee is in reliability and good potential damage from powered weapons at the cost of (usually) range and less overall damage than firearms, then (IMO), the advantage of unarmed should be in flexibility at the cost of range and damage.
The highly skilled unarmed character should always have at least two moves to perform for each AP level between 2 and 10. Because interface limitations can be overcome in a future Fallout title, the unarmed character should have access to half of these attacks with one click-hold-release. Each move should have its own benefits and drawbacks so that a healthy amount of the moves stay useful throughout the game. The moves could be split into these groups: hand attacks, hand combos, foot attacks, foot combos and hand-foot combos. For example, the character could have Jab, Cross, Uppercut, Elbow Smash, Backhand, Sucker Punch, Spearhand, and Ridgehand as standard hand attacks, each with their own AP cost, bonus or penalty to hit, DT modifier, and damage. However, the character could also gain "two-in-one" combos.
For instance, Jab-Elbow. The combo would do both moves, each at a different hex. The Jab would go into the targeted hex, and the Elbow Smash would go into the hex back and to the right. The combo would cost less AP than both moves individually, but it would be at a lower chance to hit with each attack, and would incur a fatigue cost. Another combo might be Cross-Backhand-Ridgehand, hitting the first hex targeted, the hex to the right, and the hex two more to the right.
Kicks could have the same general layout (with different moves, of course). The kicks don't even have to be crazy wire-fu'ed out. They can just be regular ol' kicks. Snap Kick, Axe Kick, Roundhouse, Back Kick, Side Kick, Hook Kick, etc. You could have the same sorts of combos. Roundhouse-Hook, Side-Back, Snap-Side-Axe.
The most complex combos would only be available when the character was fighting with no equipment in either hand, allowing hand-foot combos that could hit four, five, or even six hexes. Axe-Backhand-Round-Spear, Cross-Round-Back-Jab-Uppercut, Uppercut-Elbow-Side-Axe-Ridge-Spear. The high-skill complex combo unarmed character is like a mobile low-powered grenade, able to hit the hexes he or she wants when he or she wants from round to round. He or she never runs out of ammo, but has to accept that at high efficiency, he or she is accumulating fatigue and doing less damage than a comparable melee or firearms character. But with more than thirty moves to perform at high levels, never needing to equip or reload weapons, the unarmed character has ultimate flexibility for dealing with any close-range encounter with small to very large numbers of opponents.
Aimed shots[]
I believe that the different called shots should be made more useful overall. Eyes is clearly "the way to go" in the first two Fallout games. It shouldn't just be a "well, duh" choice. Limb crippling should be more common, IMO. Blinding should also have even more dramatic penalties, but the chance to hit the eyes should be reduced even more.
Critical hits[]
Well, overall I can say I'd like to see fewer damage multipliers, more crippled limbs, more severe penalties to hit the eyes, and crits that ignore a portion of the armor, but never bypass it completely.
Fatigue[]
Fatigue isn't something you accrue by doing mundane things. It increases as you do things like come down from chems (and super-stims), perform extremely strenuous actions (unarmed combos), and "bash" damage that's a portion of the damage absorbed by armor.
It goes up, hit points go down. Fatigue is lowered by your Healing Rate every round. If your Fatigue passes your current hit points, momma said knock you out. When your Fatigue drops below your current hit points, you wake up again."