﻿The difficulty level of non-default way is usually higher.
Only some specific zombies will chase researchers.
How to attack a boss and avoid its attacks are displayed in the screen.
Different guns use different ammos.
Completing Normal or Hard level without dying, you'll be awarded secret items.
The ending is influenced by the total score.
The final boss will use the magic which changes your sense of directions.
You can get more higher score by playing harder levels.
The weapons you got in the stage can be used in the training mode, as well.
Oil drum explosion can damage you as well.
Running and punching consume your stamina. Standing and walking can regain it.
First-aid kit can be divided into three levels depending on the efficacy.
Ammo has limitation.
Different gun has different parameters.
