Hints:

Police locker combination:
     When  entering  the Police Station and going into the door in the
top  left  corner  you  will  reach a room with zombies. After killing
them,  enter the next room, which contains the lockers. Once there, go
to  the  other side to find a locker with a light on it. The game will
prompt  for a code. The code is "0131", "0513", or "0114". Capcom made
Resident  Evil  3  hard  to  cheat  by making the combinations for the
lockers  and locations of items in different numbers and locations. Do
things differently in each game and you will get a different game each
time it is played.

Grenade launcher:
     Use  the  S.T.A.R.S  Card in the computer in the main entrance of
the  Police  Station. When you get the S.T.A.R.S Emblem Key, go to the
S.T.A.R.S  Office.  When  you  are in the office, go to the big locker
next  to  the  out-of-commission message receiver. Open the locker and
you  will  get  a Grenade Launcher. Some people may find the Magnum in
the  big  locker. In this situation, the Grenade Launcher may be found
in the Sub-Station.

Vaccine medium combination:
     One  of  the  combinations  when making the vaccine medium in the
hospital is 2 and B.

Killing Nemesis:
     If  you  can,  try and kill(disable) Nemesis at every opportunity
you  get.  Every time you manage to kill him, he will drop an item for
you. The items he drops are as follows.

1st time : Eagle part A
2nd time : Eagle part B
3rd time : 1st Aid Kit
4th time : M37 part A
5th time : M37 part B
6th time : 1st Aid Kit
7th time : Unlimited Ammo Kit

     The  Eagle  parts combine to form the Eagle 6.0 handgun. It fires
9mm  bullets  and  has  a  chance  of  causing  a "critical" hit. This
"critical"  hit  will kill any non-boss opponent with one shot, but it
happens randomly.

     The  M37  parts  combine  to form the M37 Western Custom Shotgun.
This  is  a  shotgun a little bigger than a pistol and has a very good
rate  of fire. It only stores 6 shots of 12 gauge, but is still a very
good gun.

     The  Unlimited  Ammo  Kit can be combined with any weapon in your
arsenal  to  give it unlimited ammo (duh). I suggest combining it with
the Magnum.

Mercanary Mode:
     Beat the game on hard and you'll get mercenary mode.

Explosive stuff:
     During  the  game you will see sticks of dynomite strapped to the
walls,  or oil drums lying around. Usually there are a lot of monsters
by  them.  When  you  see  them, press L2 and X and it will aim to the
objects  and blow it and all of the monsters around it into bits. Just
don't get too close to the explosive, or you will blow up.

Boutique Key:
     Beat  the  game  once on either difficulty and after the credits,
you  will  get  a  key  for  the  boutique  in the first street in the
beginning  of the game. When you go inside you can change your clothes
to  Regina's  from  Dino Crisis, or Jill's blue clothes from the first
game.

Get the STARS card:
     When  you  first  encounter  Nemesis  outside the police station,
choose  to  fight  the monster. Then run to brad's body and search him
for  the  card case. Check the item and you will get a STARS card. You
can use that in the computer in the main hallway for the safe code

Get the Rocket Launcher:
     To  get the rocket launcher, you must first defeat nemesis in the
garbage  disposal area to get the card key, then take the facility key
to  the  machine  that is next to the place where you put in the water
sample.  Use  the  facility  key in the ultraviolet ray machine and it
will  put  codes  on it. You can the return to the room with the steam
coming  out  of the pipes and go on the elevator. Use the facility key
at the door at the end and you will get the Rocket Launcher

Find hostages:
In the mini-game mercanaries you must save 6 hostages.

1 - Dario Russo - He's in the gas station.
2 - Woman - She is in the upstairs room of the press office.
3 - Brad - In the basement of the restaurant.
4 - Officer Branaugh - He's in the area where you find the fuse.
5 - Umbrella team member - in the area where you find the oil additive.
6 - Umbrella team member - in the bar. 

Get the Chronos key:
     To  get  the  chronos  key you must combine the chronos chain and
winder key.

Starting the trolley:
     The  oil  additive  needed  to  start the trolley is located in a
locked  store  room inside the sales office. To unlock it, pick up the
flashy  remote  on  a  desk to turn on a TV. You will see a commercial
about  some  product from Umbrella Corp. Make note of what the product
is.  Here  are  some  that  you might come accross: Safsprin, Adravil,
Aquacure. Go to the nearby computer where Carlos just shot his zombied
friend.  You  will be prompted for a password. Type in the name of the
product. The store room is now unlocked.

Design Chronos Gear:
     Combine  the  Gold  Gear  from  the Clock Goddess Puzzle with the
Silver  Gear. The Chronos gear is used to activate clock bells. Insert
it into the bell mechanism on the third floor of the Clock Tower.

Solve Clock Goddess Puzzle:
     The  starting  time  on  the  clock is random and the goal of the
puzzle  is  to  get  the clock to 12. The way the puzzle works is each
ball has a different value, the Crystal ball is worth +1, the Obsidian
Ball  is  worth +2, and the Amber Ball is worth +3. Placeing the balls
in  the  past  makes  them  negative(-1,-2,-3),  palceing  them in the
present  leaves  their  value the same(+1,+2,+3), and placeing then in
the  future  doubles their value(+2,+4,+6). Since the puzzle is random
you  just  need  to  do the math. Example: if the clock reads 5:00 you
need  to  advance the clock 7 hours there for you place the Amber ball
in  the  future(+6),  the  Obsidian  ball  in the present(+2), and the
Crystal  in  the  past(-1).  This gives you 7 hours and the clock then
strikes  midnight.  Again I say that the puzzle is randomized and will
not  always  be on 5:00 o'clock so you just need to do the simple math
to solve the puzzle.

Infinite Money Trick:
     Use this method to get all the infinite-ammo weapons and infinite
weapons  pack.  In the mercinary mode go to the area with the dumpster
and the hop skotch paintings (the one right behind the bar.) Go up the
steps  and  take  a right. You will then go north until you get to the
fork. Go through the door and you will be in the deadend alley that is
boarded  up  by  red  and  white  boards.  This can be done with all 3
mecinaries.  There are three dogs here. First kill 2 dogs immediately.
Then  lure the remaining dog to where the boards are stacked up. Climb
up  onto the boards. Go to the opposite end and watch as the dog makes
attempts  to jump at you. Take a small step forward and press R1 right
before  he  jumps.  Your character will jump backwards and get a dodge
bonus.  Immediately after the character dodges, press R1 again to pick
up  a  combo for your dodge bonus. Repeat this process to rack up tons
of money and time. It takes time, but it is sure worth it.

Mixing Gun Powder:
     (Note:  Additional  mixing instructions are found within the game
file on mixing.)

66 Handgun bullets * -- Gun Powder BBA 
55 Handgun bullets * -- Gun Powder AAA 
40 Shotgun shells -- Gun Powder AAB 
35 Handgun bullets -- Gun Powder AA 
30 Shotgun shells -- Gun Powder BBB 
24 Magnum rounds -- Gun Powder CCC 
18 Shotgun shells -- Gun Powder BB 
15 Handgun bullets -- Gun Powder A 
10 Acid rounds -- Gun Powder BC 
10 Cold rounds -- Gun Powder CC 
10 Fire rounds -- Gun Powder AC 
10 Grenade rounds -- Gun Powder C (mix A with B) 
7 Shot Gun Shells -- Gun Powder B 

     *  Concocting  large  amounts  of Handgun ammo wastes time, which
affects your final grade.

Max grenade launcher ammo glitch:
     With  this  code you can put more than 6 rounds into your grenade
launcher  at once. If you have 6 fire rounds in your grenade launcher,
and  you  have  138  regular rounds in your item box, combine the ammo
onto  the grenade launcher with the fire ammo in it (it works with any
ammo  as  long as the two are different) and the 6 fire ammo should be
in your item box and the 138 in your gun! No reloading.

Misc hints:

     The  shotgun can be your best friend against normal zombies. When
they come in small numbers or single file, aim and wait until they are
almost on you and fire once for an instant, brain-exploding head shot,
or aim straight at a group to hit a wide spread of targets.

     Don't be afraid to run away very fast, especially when you're low
on  ammo  or  when  you're  facing Nemesis in the earlier parts of the
game. Hand-to-hand combat with the knife against the undead is never a
good idea.

     The  Magnum almost always unleashes an instant-death head shot on
zombies,  but the ammo for it is scarce most of the way, so it pays to
save it for later.

     Because  you get branching choices for certain events, always pay
attention to your environment for clues to how the choices might lead;
they  inevitably  trigger  an FMV sequence that shows Jill escaping in
the  fashion  you  selected.  Most  of  the  time,  the  outcomes  are
predictable,  and  usually  your choice doesn't particularly matter to
the rest of the game.

Epilogues:
     Successfully  complete the game under the hard difficulty setting
to  unlock  Epilogues. Epilogues are a short diary description of each
character  in  the  entire  Resident  Evil series which describes what
happened  with  that  specific  person  after their adventure. Getting
better  ratings  can unlock the other epilogues. There are eight total
Epilogues that can be unlocked.

Medical locker combination:
     To  get the combination to the medical locker in the hospital, go
to  the  room  next to that room. Check the dead body in the corner to
find one of the following combinations: "513", "101", "498", or "517".

Magnum:
     Go directly to the Evidence Room in the Police Station. Go to the
number-based  lock  with  the  S.T.A.R.S  Emblem  Key.  Use one of the
following three passwords: "0131", "4011", or "4312". You will receive
the  Emblem  Key.  Go  to the locker in the S.T.A.R.S Office. Open the
locker to get a Magnum.

Water combination code:
     At  the  water  sample  machine  near  the dead factory, enter "1
Right"  for A, "3 Right" for B, and "4 Left" for C. That should unlock
half of the lock to the door next to the elevator.

Music Box code:
     One  of  the  codes  for the music box in the top or the tower is
Down, Up, Up, Down, Down, Up.

Run on one foot:
     When running, quickly and repeatedly tap Square. Jill will run on
one foot, and her other foot will never touch the ground.

Saving Ammo:
     In  the  begining Brad will get attack by a zombie in the BAR. He
will  throw  him  and  the zombie will come back at him. Jill will run
over, You will take control. DON'T help brad kill the zombie. You will
save 5 to 7 shots if you don't shoot. That is where you save ammo.

Jill's diary:
     To  get  Jill's  Diary  (a file), collect all thirty files in the
game  in  order.  Then the first file (Instructions Manual, blue) will
become Jill's Diary.

Barry Burton ending:
     The only way to see Barry is if ending B is unlocked. To get this
ending the following two points must be done:

The Trolley: Jump out the window:
Fighting Nemesis Type B on the bridge: Jump off. 
     After the jump off decision, the final area of the game will take
a  somewhat  different  path. You will have to fight off Nicholai in a
chopper.  It  is  recommended  that  you  bring  a  Magnum and Grenade
Launcher  (or  Rocket  Launcher  if  it  has been found). You can also
choose to negotiate with him.

Enhanced Weapons/Ammo:
     When creating ammo with the reloading tool, save enough gunpowder
to  mix  up the same type of ammo eight times. On the eighth time, the
game  will  prompt  "Do you want to create the enhanced ammo?". Select
"Yes".  This  ammo  is  more  powerful,  may  have  slightly different
effects,  and  once  loaded  into  a  weapon  will  change  it into an
"enhanced  weapon".  Once you have loaded a weapon with enhanced ammo,
do  not  reload it with regular ammo. You can only create two types of
enhanced  ammo:  9mm handgun bullets and shot gun shells. Also, do not
combine enhanced ammo with regular ammo.

Make your own shotgun:
     In  order  to make a shotgun you must have gunpowder BBB, grenade
rounds, and the mixing tool. Mix gunpowder BBB with the grenade rounds
to  make  shotgun  parts.  Next, mix the shotgun parts with the mixing
tool to make the shotgun.

The three jewels in the clock tower:
     When you enter the room in the clock tower with the three statues
holding trays, take the obsidian, crystal, and amber jewels from them.
There  are three clocks on the wall besides the two dead bodies. Going
from  left  to  right,  place  the  amber jewel in the first tray, the
obsidian  jewel in the middle tray, and the crystal jewel in the third
tray. The middle clock will open and you will get a gold gear. Combine
it with the silver gear and place it in the slot on the third floor.

Easiest way to get all epilogues:
     first  complete  the  game as quickly as possible don't fight the
nemesis  just RUN for the exit once you have completed it you will get
an  epilogue two or three costume and more importantly the mercenaries
game  then  use  mihail  to  get  unilimted ammo assault rifle and the
rocket  launcher.now have some fun and just work your way through with
that lot you can kill the nemesis in two hits (anyone of his mutations
apart  from  the  last  one!!!!)  then it will tak time but it will be
extremly easy.

Save ammo:
     When  you  get  the  shotgun and the lighter oil run to the other
which  is near the entrance to the bar there are three zombies and two
that  are  eating you don't need to shoot them just run past them this
is another place to save ammo.

Guns against the monsters:

Zombie:
     The  shotgun and the magnum are best to kill zombies. Not so good
with the handgun which takes about 8 bullets to kill them.

Dog:
     Use either your shotgun or magnum. Best not to use your handgun.

Crow:
     The best gun for a crow is a hand gun with one shot and it will die.

Drain Demios:
     The best guns are the shotgun, magnum and grenade launcher if found.

Spider:
     Use your shotgun, magnum and grenade launcher.

Hunter:
     The  best  guns  are  the Assault Rifle, Grenade launcher. Not so
good with the shotgun if you use it you will need health spray.

Grave Digger:
     The best is acid rounds, freezer rounds maybe flame rounds if you
have the shotgun or The Assault Rifle bring lots of herbs.

Slugs:
     You meet these in the Hospital but the best gun is the handgun.

Nemesis:
     Assault Rifle is good but bring health sprays. Magnum not so good
but  only  if  he  is  weak, shotgun not so good same with the Magnum,
handgun never good against Nemesis or you will meet hell, Flame rounds
extremely  good  against  Nemesis, Acid rounds alright, Freezer rounds
good  and the Rocket launcher is good for the Last mutation of Nemesis
until you get him into the bullets of the railgun to blow him.

Places where you will meet Nemesis:
     The  first Nemesis you come across is the beginning of the Police
station and he is very easy.

     Once  you've finished from the Stars Office, when you go down the
stairs, Nemesis will jump through the window.

     When  you  arrive  in  the  Restaurant  you will be introduced by
Carlos, then Nemesis drops by.

     Once  you  have  finished in the Sales Office, when you head out,
Nemesis  will come through the door but you can either kill him or run
away. Note! He will follow you to the parking lot.

     When  you  arrive back to the City Hall Nemesis will be there but
just run past him and he will do nothing.

     In  the cable car, Nemesis will be there but don't kill him. Just
go back to the other side and then Mikhail will kill him and himself.

     When  you  have solved the Music Box, go back down the ladder and
Nemesis  will  go through the door but you will have a option. Best is
to use the light on him.

     After  you  made  the  clock  work, the movie will be shown where
Nemesis destroys the Helicopter, then kill him until he walks into the
fire.

     Once  you  have finished in the Hospital go back to the main hall
and  Nemesis  will  jump through the roof. But he is uglier now but he
doesn't hit you he has got long tentacles and he can grab you from any
distance. But run back to the save room where Jill is.

     Once  Carlos has left, Nemesis is waiting for you outside but run
past him until you reach the park outside the Clock Tower.

     When  you  have  finished  the  park, one of the door will now be
unlocked.  Go through and up the stairs straight into another Nemesis,
he  will  burst  through the bridge so push him off and enter the dead
factory.

     If  you  have  done  everyhing  right,  the  door  to the garbage
disposal will be open. Go through. Nicholai will be killed by Nemesis,
put  in the System disk and enter the door. Now you must face Nemesis.
Make  sure  you  have  the Grenade Launcher and the Magnum and LOTS of
health  sprays  or herbs. He will be much harder but try and shoot the
steam pipe which will do some damage to him.

     The  last  mutation of Nemesis is by the Rail gun. You must hurry
because you have got a few minutes to get out of there. When you see a
massive  Rail  gun  and  batteries that are marked 1, 2, 3 push in the
first  one  and Nemesis will appear and you will see him mutating into
his  last  form. Take it out with your Rocket Launcher and a few shots
with your flame rounds and he gives up, staying in his position. Hurry
to  push the other batteries and the rail gun will shoot at him. Note!
It  takes  15  seconds  to  charge  up  two  bullets  and  he  is  now
unconscious.  Enter  the door and the options will appear when Nemesis
will  come alive if you want. You can escape and enter the door and up
the  Elevator to the helicopter with Carlos and leave when the Nuclear
bomb hits the city and wipes out everything.