Exit the classroom by going south.

Go east.

Take the fire: extinguisher from the wall, then go east.

Go north, into the janitor's closet.

Take the gun from the table, then leave.

Go back west, then north, into the classroom.

You'll now have a boss battle against the telekinetic Alucard, where you'll need to shoot him to defeat him. During the fight, Alucard will throw dead bodies at you, which you'll need to shoot to avoid taking damage. He'll then throw a chair towards you.

Once defeated, Alucard will hide behind some desks and throw out a key. Pick it up. You can optionally click the desks he's hiding behind to expose him; killing him will unlock the Overkill medal.

Leave the classroom by going south.

Go east twice.

You'll be confronted by one of the shooters, and given a choice between "Please spare me!" and "Go eat dick"; picking either option will result in him shooting you, causing you to lose 1 unit of health. Instead, click the gun in your inventory. The shooter will then claim he was only trying to scare you, and you can choose to spare him or kill him; your choice has no effect on the game, but if you kill him, then shoot his body, you'll unlock the Brutal medal.

Go east.

Click the handle of the discolored locker, the 4th red one along; inside you'll find a medicinal herb. Take it. Using it will restore your health. However, since the game includes a "restart from checkpoint" feature, which fully restores your health, it's a little useless.

Click the key in your inventory to unlock the gate.

Go north, into the women's restroom for another boss fight.

During the fight, the lights will go out, and Hanzou will begin moving around the room in a Z: like pattern. You need to shoot Hanzou by following his night: vision trail.

It's a difficult fight and one you're unlikely to win on your first attempt, as it's impossible to avoid his attacks, which means you'll need full health to beat him. If you fail, you can simply reload from checkpoint and return to the bathroom to try again.

Hanzou defeated, he'll drop a pair of night: vision goggles. Pick them up, then leave.

Medals: For two optional medal, go into the boy's bathroom, and open the first toilet stall door. Click through all of the speech: bubbles. After the occupant throws several pieces of poop, you'll unlock the Scat Man medal.)Next, click the handle of a urinal four times; once it's clean of urine, you will unlock the Marc Summers medal.

Last, click the sink faucet to overflow it, unlocking the Tap That medal.

Back in the hallway, go east.

You'll encounter a girl begging to be killed. You can click the gun to kill her, or simply carry on going east.

Go into the teacher's lounge.

Use the fire extinguisher to put out the fire. The door is locked, so leave by going south and go west 6 times, and into the first classroom.

Activate your nightvision goggles to reveal a key on the floor.

Return to the teacher's lounge and use the key to go to the final boss fight.

After exhausting the dialogue, Cassandra will kill the other goths and transform. To defeat him, you need to repeatedly shoot him in the testicles as he moves left and right.

Cassandra has three attacks; throwing barrels, firing a projectile from his eyes, and stamping his feet, causing debris from the roof to fall from above.

Concentrate firing on his testicles, shooting the barrels when he throws them to destroy them.

When his eyes begin to glow; you need to quickly shoot both of them to prevent his attack.

When he stops moving and raises his foot, a piece of rubble from the ceiling will fall. Shoot it to avoid taking damage.

To make things easier during the fight, shoot at the tank on the ceiling labeled FLAMMABLE. Once destroyed, it will blow up the wall, allowing the cops outside to shoot at Cassandra, damaging him. You'll also unlock the Bruckheimer medal.

When you've dealt enough damage to the boss, he will collapse, ending the game, and unlocking the final medal: Save the Day.