Boss 1: Stinger (a giant scorpion) | Boss battles Resident Evil Zero HD Guide

You fight this boss during your exploration of the Ecliptic Express train. He appears in the upper level of the restaurant car, but only after you collect the ice pick from one of the neighboring room (a storyline item).

Use the shotgun and aim at the scorpion's head.

Stinger is a giant scorpion. It is not too difficult an opponent, but it is a better to be careful here, because you can quickly lose lots of health points. Right after the fight starts, dash up to the monster and aim the shotgun at its head. It is very important, because damage dealt by shotgun depends on the target itself. After you fire, move away quickly (you can either retreat in the normal way, or use the combination of buttons, thanks to which you quickly turn around by 180 degrees), because the monster then makes a characteristic nose that precedes its attack. Continue using the shotgun in the way described above, and remember the you need to reload after you fire it twice.

If you are up against a wall, continue the "regular" fire only

Sooner or later, you may be pushed against the exit door. In such a situation, only continue your fire, and do not try to squeeze by the scorpion into the other part of the car. With a bit of luck, you will be able to defeat the scorpion using the shotgun only, but if you run out of ammo, select the pistol quickly. Also, keep an eye on the character's health and use either spray or herbs, if necessary.

Note - if you are fighting the battle a Rebecca, you need to attach even more care to keeping her alive, because she is not as tough as Billy. The battle itself, in the case of Rebecca, is the same as for Billy.