Zombies are a staple of Sega's on-rails shooter arcade game series House of the Dead. While these undead creatures share many common traits of typical horror zombies, there are a number of factors that set them apart. The zombies of HotD are primarily man-made, genetically engineered via cloning procedures or by introducing an as-yet unnamed mutagenic compound into the human body.
The mutagen causes necrosis, bleeding and aggression. Although it is unknown whether the creatures are the dead reanimate and feed on human flesh they certainly display several common characteristics of the traditional zombie. They have varying skin colours in each game, the standard ones walk with a lumbering slowness although other breeds are fast. Unlike zombies featured in other games, these zombies have shown minor intelligence, such as being able to utilize terrain and weapons. Another departure from traditional zombies is that these zombies actively pursue their targets with the intent of killing them, as many of them utilize weapons and other blunt objects to attack.
These particular zombies are shown to be different from traditional undead in other ways - while Zombies are usually stopped dead with a shot to the head (or the removal of it) most if not all of the zombies in HotD can survive, and actively pursue their targets, after having gaping holes blasted through their heads, or in fact the entire head being blown off, although this only usually occurs in the tougher ghouls. They are also suprisingly more intelligent for the most part, having the ability to use tools and weapons, as well as being able to negotiate obstacles and cover with ease. Some appear to have the drive to defend themselves, protecting their faces with iron masks, axes and other objects. They are also only partially shambolic - most run or pace towards their targets, while others shamble for a while until shot, after which they will hastily pursue the attacker.
The HotD zombies sometimes exhibit cannibalistic tendencies like classic zombies and have sometimes been seen feeding on the living, though this is usually the case of zombies that do not carry any weapons. They are not compelled to feed on humans and do not pass on any infection that reanimates their victims.