Well, I have 100 in small guns. Is there any point in increasing past 100, or can I move on to, say, barter or science?

100 in any combat skill is really pretty worthless, you need 150+ to actually be sure of a good targeted attack. It is fine if you are using a shotgun or a automatic weapon at close range.. but you lose lots of efficiency at range. Or if you are using the fast shot trait 100 might be ok cause you get more shots, but for a good critical you need high skill in any combat skill.

I suggest 150+ in your main weapon skill. I actually have 150+ in energy and big weapons at the moment and rarely miss at any range.

Barter is a worthless skill in fallout 2 really. It only really is used in dialog transactions, and there are not that many of them. The value of guns is so high that you can easily buy back your caps with your spare guns you have laying around, no matter how much you pay for a dialog transaction. The only one guy that it matters with is Dr. Fung for the implants, since you can't buy that money back.

Don't put points into science imo, just trade guns for big science books untill it reaches 91% then put points in since you can't raise the skill anymore with books past 91% with books, that goes for any skill you can raise with books or NPC training.

Unless you want to recruit Skynet for which you'll need 120 in Science(if I remember correctly).

Combat skills I'd say round out to about 150% for those where you can target a body part, and maybe 130% for burst only types. With other skills, you're okay to stop increasing at about 100%. The only potential exceptions are speech and sneak to 120% (and maybe steal if you dont want to use save/reload at all). Science I'd only increase to 70-80% if you want dermal implants, and 120% only if you want skynet with the robotic brain.

You also need 90%+ in Doctor to access the computer to get the implants perk.

If you're playing Unarmed/Melee you'll be wanting those skills up to 200 :shrug:

Yes, you should take it up past 100. Allow me to explain

The combat system in the original Fallout games actually played out very well on paper, (so much so, that if you were a particularly adventurous D&D style gamer you could play it as a pen and paper game and even print your character sheets right out of the game). The game essentially determined whether or not you were going to hit someone (and what your chances of hitting them were) much the same way a human Game Master would in a pen and paper session; it would take your base skill for the type of attack you were using, then subtract your opponents current armor class, deduct perception penalties if necessary, and deduct any range penalties that may apply to the type of weapon your using (IE hunting rifle at close range/shotgun at long range). The end result is your chance to hit, with further penalties for aimed shots (head, eyes, etc) And you always have a 5% chance to miss.

So lets say you have 100% in the small guns skill, your target is at very long range for your weapon and perception (about a -10% chance to hit), your enemy has an armour class of 20, and an additional 3 armour class from extra action points from his last turn. That translates into 100 - 10 - 20 - 3 You chance just to hit your target is 67% - 5% (that constant 5% chance you'll miss). Say you're making an aimed shot for the eyes, that's another -20% so 42% chance to hit.

If you were dicing it up you'd essentially roll two D10 dice, any result 42% and under means you hit your target, any result over means you miss, a 00 means you critically miss and something bad happens to you (gun blows up in your face, lose your ammo, if you're name is Vic you somehow manage to cripple both your legs)

Bump your skill up to 170 and you're looking at 170 - 10 - 20 - 3 = 147% - 20% for your aimed shot to the eyes = 127% which really comes out to 100% and then deduct your 5% chance to miss and voila, you have a 95% chance to shoot his eye out.

(While aiming for the eyes is a good way to score crits often, if you're not one shot killing with eye shots I always found it better to aim for the head. Easier to hit and carries the chance of knocking the opponent out and removing them from combat for a few rounds while you deal with their friends)

Hope that clears things up for ya.

IMO targeted areas really should be based on the enemy, their weapon, and your position. No single target is always the best. For example:

Enemy unaware, any weapon, 90+ chance - Eyes or burst from 1 space away - (exception is deathclaws/supermutants unless you have gauss rifle/gauss pistol/energy weapon or equivalent). Reasoning: You may never get the same hit chance again meaning that this is your best shot to get a 3x crit or insta-kill with your mass-damage methods.
Big Weapons - Arm - Get them to put away those rockets and flamethrowers ASAP! They are almost impossible to be missed by and can do significant damage on a solid hit
Any while you have a corner to duck behind - 1 Leg - spread the enemies arrival around the corner by slowing down the back row, just be sure to leave enough AP to run out of sight at the end of each turn
Multiple Melee enemies with ranged present - all but one melee's leg until crippled or they reach player then use the ranged priorities - Melee enemies also tend to run away when crippled and hurt. Leave the least threatening one alone though since you want the human shield to block gunfire.
Other 2-handed weapons Rifles, semi-auto shotguns, automatic shotguns, and plasma rifles are very hazardous to your health. Assault rifles aren't so big a threat for some reason.
Melee Only - 1 Leg each then eyes - as long as there is space to run circles around the crippled enemies you should be worried about staying out of their reach
Ranged, >90 chance - Eyes - Best damage, chance of blinding to reduce accuracy.
Any, primary target already crippled, >85 chance - Head - knockout or bonus damage

These are just some general tactics, the perfect one to use depends on the combination of enemies, their positions, your skills, and your position. It also tends to change each turn.

Generally I one-hit kill just about anything with a laser rifle to the eyes. That includes Super-mutants. Another great one vs supermutants is the Gatling Laser, that just rips them to pieces. I wonder if the retarded guy upgrades those, I never really checked...

1st or 2nd game? Wimpy, normal, or tough? With or without the sniper perk, better crits perk, and 10 luck combo? There are a lot of variables, don't forget that you spend a lot of the game without consistent 1-hit kills.

On 1st game its energy weapons all the way for endgame ownage if you don't mind building a skill you don't use for 3/4 of the game but on the 2nd, small guns does just as well IMHO. I've always found the endgame of 2 easier with small guns, progressing from 10mm pistol -> 44 magnum w/speedloader -> Combat Shotgun -> .223 Pistol -> Gauss Pistol. Carry a hunting rifle->sniper rifle->Gauss Rifle for long range areas or your favorite SMG->burst shotgun for short range bursts as your second weapon. On top of guns being roughly equivalent to energy in FO2, you have more points to throw into the non-combat skills like science.

i think you need 200 unarmed for slayer.
is there anybody who can verify this

You need 80%.

200 is just a good number to go for.

You'll need a ridiculously high traps skill if you want to bypass a door maze at the end of the game. Can't remember the exact number, though.