STICKMAN SHOOTING ZOMBIE SQUARES GAME. UPDATE PLAYER MOVEMENT WITH WASD keys. ZOMBIES DIE TO BULLETS. ZOMBIES SPAWN FAR AWAY AND MOVE SLOWLY TOWARDS THE PLAYER. PLAYER DIES TO ZOMBIES. MOUSE IS USED TO AIM BULLET DIRECTION AND TO BURSTFIRE BULLETS WITH AMMO. DEAD ZOMBIES DROP AMMO. HIGHSCORE IS SAVED. IF MATH.RANDOM < 0.05 SPAWN ZOMBIE