The ammo you want:
Every time you kill the big guy from Resident Evil 2 he will usualy drop ammo. The way to get the best ammo is to kill him with certain types of ammo. Let me explain, if you kill him with the handgun you'll get shotgun ammo so you always get the next best ammo. So, from handgun - shotgun - flame rounds - acid rounds - grenade rounds - magnum ammo.

Beat the final boss:
When your at the heliport fighting that mutant freak, use A or B to spin. Then while youre spinning use your shotgun (make sure you save ammo). He takes 3 clips and in no time he'll evolve, then do the same thing until his dead.

All weapons & ammo:
To start the game with all weapons and lots of ammo you must take the first route (the easy one) and pick up ammo on your way around. When you find a new weapon and most of the ammo around you, you must let a zombie kill you. When you get to the game over screen dont push anything and so you won't be to continue. after this it will say save weapons you have found. Obviously you say yes and next time you come on the game load game and you will start with all of the ammo you found and the extra gun. (It usually takes about 30 minutes to find a new gun) do this 3 times and take a different route each time to get all of the guns.