Warning: The following contains information that will help you solve Fallout. Please, DO NOT READ FROM START TO FINISH. You'll spoil the game and ruin any chance of ever becoming a good, decent person. So go ahead and cheat, you derelict.
SECTION I. Vault 13 Cave Entrance.
Search the corpse near the vault entrance and equip yourself. Kill all rats in the area (there are twenty of them). That should give you 500 experience points. In most cases you will get hurt by the rats. At this point in the game it's good, because you get a chance to use your First Aid and Doctor skills. While your character is 1-5 level, do it whenever you can as it earns you experience.
Now it's time for the wastes. The exit from the caves is in its western part. Once you're out head for the Vault 15.
SECTION II. Shady Sands.
On your way to another vault you will eventually discover another green circle on the map. That's the village of Shady Sands. Drop in.
First of all, holster your weapon. Most of the NPCs will not converse with you until you do. Talk to Seth, the guard at the gate. He will tell you of the Radscorpions' problem and offer to take you to Radscorpion caves.
SECTION III. Radscorpion caves.
This area is pretty straightforward. Just kill all of the Radscorpions and be sure to collect at least one of their tails. Exit the caves.
SECTION IV. Shady Sands (revisited).
Later on you will need a rope. Seth has one. Trade it for something you don't actually need (Radscorpion tails, for example). Visit local healer and give him a Radscorpion tail for the antidote and some experience. Find the traveling merchant (he's in the house near the village gate, the one in blue pants) and ask him about Junktown and Hub. They will appear on your world map. Exit the village.
SECTION V. Vault 15.
Descent into the vault, find the elevator shaft and use the rope on it. You will gain access to Vault 15 levels 2 and 3. Make your way to level 3 and head for the south-eastern corner. There you will get some experience and will be informed that you won't get the water chip here. Exit the vault. Head for Junktown.
SECTION VI. Junktown.
Find Killian Darkwater, the mayor of Junktown. Talk to him. In the middle of the conversation there will be the assassination attempt on Darkwater. Kill the assassin and get back to chatting with Killian. He will propose you to talk the confession out of Gizmo, local Mafia boss. Accept his proposal and visit Gizmo. Talk to him about the failed assassination attempt and offer yourself as the man for the job. Then Gizmo will confess that he wants Darkwater's head. It's just what you need. Return to Killian and give him the tape with Gizmo's confession.
Accept his offer to participate in Gizmo's accusal. Of course, Gizmo will fight and, of course, you will have to kill him and Izo, his bodyguard. After you're done talk to the guard captain. He has another task for you. You are to bust Skulz, the gang that originally worked for Gizmo. Visit Scum Pitt at 20:00 and you will see the bartender killing the Skulz member. Steal the urn on the bar and show it to Vinnie, Skulz leader. He can be found in the back room of Crash House. Vinnie will accept you in his gang and offer you to take a part in the bartender's murder. At this point you can either join him right away or run for the guard captain. In any case, once you are in the bar, kill all the Skulz members and return the urn to the bartender.
That's it. Leave Junktown for Hub. On your way out you may want to help Philip out with the dog that doesn't let him in his apartment. You can plainly kill it (no dog - no problem) but better give it an iguana-on-a-stick, it's worth more experience.
SECTION VII. Hub.
There is much to explore in Hub. I'll just cover some of the more interesting things.
First, the weapons merchant in Old Town has the most powerful melee weapon in the game - the super sledge. To get it, browse his selection and then ask for something that has more punch.
Next, you might want to find out the cause of the trading caravans disappearing (talk to merchants, they will complain about it eventually; along with it you will be informed of Necropolis, Boneyard and Brotherhood of Steel locations).
Talk to Butch, the leader of Far Go Traders, he will ensign you on a job of finding the lost caravans. Ask him about the Death Claw, then go talk to Beth -she runs the weapons shop here in Hub. After you do it visit some madman in Old Town, he's always by the house in which Harold the mutant lives. The madman will refuse to help you until you talk to Harold. Then he will take you to the Death Claw cave. Take it out. If you have difficulties let it live for now and return here after you visit Necropolis. In the cave you will find a dying mutant who will give you the holodisc. Show it to Butch for some money.
Then talk to the guy who runs FLC. He will advise you to seek work with Dekker,the underground leader. Go to the night club which is across the street and persuade Kayne to let you in. Dekker will offer to dispose of a merchant who lives in the Heights. Accept and frame Dekker telling the Sheriff about the job. You will be asked to join the Dekker's arrest. Agree when you are ready and kill Dekker and all of his gang. The Sheriff and the deputy are not much of assistance. Now that's a good place to store your supplies. Don't forget to visit the police station for the rest of your reward.
You may also wish to join the thieves' circle located in the basement of one of the houses in Old Town. Talk to their leader, he will ask you to steal the necklace from the merchant living in the Heights (it seems that everyone has a knife into the poor guy). To enter the merchant's house you will need to wait till it's dark and SNEAK into it during the guards change. There find the chest containing the necklace, grab it and get out. When you give it to the thieves' circle leader you will be presented with electronic lockpicks.
In Old Town there is a group of thugs holding a Brotherhood of Steel initiate as a prisoner. Kill them (the nasty one's armed with a combat shotgun) and release the prisoner.
Talk to the water merchants (they can be found in the southern part of Hub) about the water chip. Refuse their offer to supply your vault with water for 100 days - you have plenty of time. What is more important they will tell you that the ghouls of Necropolis refused to trade with them. That means they have a stable source of water. Could this be a water chip?
There is an opportunity for you to take a job of guarding the caravans. It pays, though not much, and usually it's worth some experience. But I, for myself, consider that job a waste of time. Now it's time to return to Shady Sands. Something's happening there.
SECTION VIII. Shady Sands (revisited).
Seth will tell you that Tandi, the daughter of the village elder was kidnapped by Khans, a group of raiders. Go talk to the elder. He will give you the quest to return Tandi, a spear and his blessings. Now visit Khans.
SECTION IX. Raiders.
Go straight to Garl, the Khans leader. Tell him that you're taking the girl and challenge him. You will fight bare-handed. Kill him. If you aren't strong enough, the best tactic is to strike for his legs and, once he's down, for his eyes. After you defeat Garl take Tandi to her father for the reward and return here. You are not finished with the raiders yet. Kill 'em all. Now you are finished. Head for Necropolis.
SECTION X. Necropolis.
You will enter Necropolis in the area called the Hotel. Your task is to get to the Watershed using the sewers. Eventually you will encounter the group of peaceful ghouls who live underground. Talk to their leader and share your problems with him. You will know that they do have a water chip in Necropolis and are using it because their water pump is broken. Agree to find the parts for the water pump and fix it. In the center of Necropolis lives Set, the head of the city. He is sick and will get killed later on in the game by the invading super mutants, so why not kill him now? Besides, he has some quite valuable items. Before you kill him he may tell you that a bunch of huge mutants is causing him problems at the Watershed. Go there. You will see, yes, you guessed it, a bunch of huge mutants. Find their boss, Harry. He will talk to you. You will get two options - agree to follow him to the Lieutenant, and it will be very, very hard for you to survive there, or refuse, which will cause Harry to attack you. He has a laser rifle, so make sure he dies fast.
Other super mutants will also attack you. One of them is armed with a flamer and that makes him even more dangerous than Harry. After you dispose of them descent to the sewers where Larry the super mutant stood. There you will find some junk parts. Return with them to the peaceful ghoul and he will give you three books on electronics. Go back to the house where you encountered Harry and REPAIR the water pump. Descent into the sewers in the southern part of the house. There is a vault here. Find the water chip and leave Necropolis for the Brotherhood of Steel.
SECTION XI. Brotherhood of Steel.
Talk to the guards. One of them will charge you with the quest to bring them something from the Ancient Order AKA Glow. Accept the quest and leave the hospitable Brotherhood. Before you go to the Ancient Order it would not hurt to wander into Boneyard.
SECTION XII. Boneyard.
Boneyard consists of four main parts: the downtown where the Blades reside, Boneyard Adytum, the library, home for the Followers of the Apocalypse and the fortress of the Gun Runners. Go to Adytum and talk to Miles, their chemist and Zimmerman, their mayor.
Zimmerman wants the leader of the Blades dead blaming her for the death of his son, and Miles wants you to get him the parts to fix the hydroponic farm. Go to the night club where the Blades are. Talk to their leader. She will prove her innocence by giving you the holodisc with the Regulators transmission. Hmm, it's obvious that the Regulators are much more than just the guards for Adytum. Head back to Zimmerman and show him the disc. He will get killed and you will get a full-scale war with the Regulators. You have no choice but to kill them. Now visit Nicole, the founder of the Followers of the Apocalypse. She will tell you to find out what is happening in the Cathedral. She is sure something sinister is going on there. Let her know you will look into it. Now for the Gun Runners. To get to them one has to deal with the Death Claws. Once you entered the Gun Runners fortress talk to Gabriel, their leader! and agree to destroy all Death Claws so the Gun Runners could move out. Gabriel isn't very happy with the situation in Boneyard - his only clients are the Regulators and he cannot move out because of the Death Claws. Return to where you saw the Death Claws, kill them on the surface and proceed to the basement.
There you will find the Mother Death Claw and the eggs. Take care of them and return to Gabriel. He will decide not to move out as you eliminated both the Death Claws and the Regulators. Pick up the junk parts lying where the Death Claws were and take them to Miles, then to Smitty and then again to Miles. That's it. Leave Boneyard and head for the Glow. Make sure you have a rope and two packs of Rad-X in your inventory.
SECTION XIII. The Glow.
Stop in the square next to the Glow and take Rad-X until your radiation resistance is 100%. Without it you might get fried. Now go to the Crater, find a beam and tie your rope around it. Descent to the crater via the rope.
Your task here is simple. All you need to do is find the corpse of the paladin (the one in power armor) and get the holodisc from him. He is lying somewhere on the first level. But the Glow is much more interesting than that. In total you will need to collect three access cards which will give you access to different elevators, REPAIR the power generators on level six, get to level five, dispose of the sentry robots and collect the stuff. There is also a very advanced computer from which you may know what are the super mutants and where they come from. Return to the Brotherhood.
SECTION XIV. Brotherhood of Steel (revisited).
Now the astonished guards will let you in. On the first level make sure to visit the training facility and talk to the paladin there. He will thank you for saving the initiate in Hub and offer you an item of your choosing as a reward. I recommend taking the power armor. Get it from Michael, the guy in combat armor near the supply room. On the second-third floors there are a workshop, a library and a medic who can make operations permanently increasing your stats. In the workshop you may talk to the guy who's repairing a suit of power armor. If you get him a systolic motivator from Michael or steal one from Rhombus, the head paladin and REPAIR that armor you can have it, but do you really need it if you already have one? On the fourth level the Council of the Elders and the leader of the Brotherhood are. Talk to them. They will confess that there are rumors about some army from north and ask you to investigate the northern regions. Accept the quest and leave the Brotherhood. It will be useful now to visit Boneyard Adytum.
SECTION XV. Boneyard (revisited).
When you're there go talk to Miles about your power armor. He will ask you to bring him some magazines on chemistry from the librarian in Hub. Once you're back he will make your armor even more powerful. By this time you should have a plasma rifle. Bring it to Smitty and he will upgrade it to Turbo Plasma Rifle, the one and true energy weapon, nearly as good as an alien blaster which doesn't look so good. Now you're ready to take on the military base which is situated in the north-western corner of your world map.
SECTION XVI. Vault 13.
Aren't we forgetting something? Ahh, yes! The chip. By this time you should have at least thirty days before the deadline which is more than enough to get to Vault 13 from any point on your world map. Well, bring the chip back to your vault Overseer. He will get worried about the mutants and ask you no less than to destroy the source of the mutations and the mutants leader. Depart for the military base.
SECTION XVII. The Military Base.
Once you find the military base and see the guards you may return to the Brotherhood of Steel and persuade the Council of the Elders to assign three paladins to help you but since they don't follow you into the base building anyway that would be a waste of time. So, dispose of the guards. Take a radio from one of them scream in it that you're being attacked by the unknown enemy. You will get some experience for that. Enter the building.
The military base itself is pretty straightforward. Just kill everything that moves, you have no friends here. As for the force fields, plainly go through the red ones, you will take some damage but no much, and REPAIR the force field emitters for the green ones the final level you will encounter the Lieutenant and VanHaagen, the guy from the Cathedral. Yes, you can kill them too. On that very level find the room with lots of computers and exploding technicians. You can prevent them from exploding by shooting them. Use your SCIENCE skill on the main computer and initiate self-destruct sequence. Get out of the base before it blows up. Now, what was that guy from the Cathedral doing there?
SECTION XVIII. The Cathedral.
In the Cathedral you will be accompanied by the group of Followers scouts. Find the woman Nicole told you about and tell her "red rider". She will tell you about the secret door the key to which only Morpheus has. Find Morpheus (take stairs up). In any case it will all end up by fighting him and the Nightkins.
Take the key from Morpheus' body, get back to the ground floor, open the secret door and descent.
In the basement find the strange wall near the bookcases which is marked on your automap as a passage. Eventually it will open and you will encounter another servant of the cult. The simplest way to deal with him is to kill him.
Behind the secret passage is a vault entrance. From there make your way to the third level, find another secret passage and enter the corridor of flesh. You will get damage advancing this passage and may finally have your eyes poked with some bone or alike. In that case use your DOCTOR skill to restore your vision before the battle with the Master. Come close to the Master and he will talk to you.
Don't take his offer to join him. He will attack. Take cover behind one of the columns and shoot him periodically with your turbo plasma rifle. It'll take about from four to six shots. Once per three turns the corridor will spawn a super mutant but when you kill the Master it'll be over. The Master's death initiates self-destruct sequence on the nuclear ware! ad that's on the fourth level. Escape the Cathedral and that's it you've completed Fallout.