HOTD - 4 introduces a great many new features while maintaining the overall feel of the HOTD franchise.
A new weapon. Your main weapon is a modified version of sub-machine gun.
New reload technique. A simple shake of your sub-machine gun delivers a new clip of rounds. With all those Zombies, you won't want to run out of bullets.
Hand Grenade. Push the button on the side of your sub-machine gun and watch your character toss a fragmentation grenade at the enemy. You'll want to save them for when the crush of Zombies is too much to drive back with your sub-machine gun.
Gun Shaking Combat. If a Zombie gets hold of you, shake your sub-machine gun and wiggle free. You'll momentarily stun the Zombie giving you a short window of time to reload and fire!
Two violence and blood settings let operators go from mild to extreme gaining greater location and community acceptance.