Minecraft's zombies may look and sound great, but they are hardly a serious threat. Even when playing on the highest difficulty, where they do much more damage and can break down doors, their slow speed and idiotic artificial intelligence only make them dangerous if the player intentionally fights them, and even then, someone with a decent sense of timing and a little patience can easily slay them with their bare hands.
As the game progresses, zombies do start to hit harder and live through more attacks thanks to Minecraft's area difficulty system, but even the most well-equipped zombie can easily be dealt with thanks to their awful speed. But simply making the undead move faster is not a great option—their basic model is not built for anything beyond walking speed.
Quick-moving enemies are not a good thing to have during the extremely early stages of the game, and there is a certain charm to their shuffling walk that Minecraft might just be worse without. This is why the changes made by Zombie Awareness are so good for the game; they make the living dead a much greater threat while only barely affecting their physical capabilities.
The most obvious change brought about by Zombie Awareness is the large swarms of undead that can sometimes appear at night. But the mod does not simply increase how often zombies appear; in fact, lucky players or those down in the caves may not even see more than one or two moving corpses in an entire night.
Instead, zombies can now group together with any other undead that they see, and if they locate a tasty-looking player, the entire horde will begin heading towards them. Groups like this can also spawn in all at once, and those bands can then merge together with any other nearby packs of undead, allowing for absolutely massive swarms of zombies that will try to charge the player down, forcing them to either run or attempt to fend off an entire army.
Increased numbers and group AI are not the only enhancements that the living dead have received. Their ability to detect players has been made significantly better as well. They can now see further and will begin moving towards any sources of light that they detect in hopes of chowing down on a player's innards.
Their ears have also been improved, and if one begins mining near a zombie, they will be able to hear that sound and will attempt to move towards it. Even their sense of smell has been enhanced by the mod; wounded players will occasionally leave bloodstains behind, and any zombies that catch a whiff of these stains will start heading towards them.
This means that injured players will have to keep on the move or find a truly safe location to heal up in, and those who think they can just hide for a few minutes while their health regenerates are instead likely to attract even larger hordes than they had to deal with in the first place.
All of this comes together to give the player a lot more reasons to construct their homes with a mind toward the undead. Simple base defenses such as walls are almost a requirement for those who want to build throughout the night, and on hard mode, it is an extremely good idea to have multiple ways to exit one's home.
The increase in numbers also encourages traps and grinders to be constructed to catch any of the walking dead who come near, and with a little work, one can turn those nightly invasions into a great source of almost free food and iron.
And of course, lighting one's home becomes far more important than it normally is, as just a few iron golems will not be enough to protect the player for more than a night or two.
The changes also mean that attempting to directly fight off the undead is much more difficult, though certainly not impossible. Their greatest weakness, speed, is a major issue no matter how large a pack gets. Skilled players can still strike at members of a horde without getting too close, and so slowly whittle the group down without taking much damage.
However, the increase in numbers means that it is a lot harder to keep track of the location of every zombie in a crowd, and when in forests or other cluttered areas, a pack may get broken into a large number of smaller groups, which can be quite difficult for the player to safely manage.
Adding to this difficulty is the fact that the increased detection abilities of the undead force players to always watch their backs during a fight, as it is quite common for wandering zombies to spot a player and move in from behind.
Altogether, this means that fighting the undead has become a much more difficult prospect in which careful positioning and awareness of one's surroundings is required just to survive.
By default, Zombie Awareness is a hard mod, but players can tweak every aspect of the difficulty to their liking through the plugin's impressive configuration files. When using the basic settings, only zombies and skeletons will use the new AI, but any of the other monsters in the game can be given the undead's sense of awareness by simply removing their name from a blacklist.
Each one of those enhanced senses can also be made stronger, weaker, or disabled altogether, and the various parts of the group intelligence systems can be disabled as well. The various spawning rules can also be adjusted as needed, and it is a simple matter to increase or decrease the distance at which zombies can spawn, how often they appear, and the chance of large packs generating all at once.
The player can even lower the maximum amount of undead that can exist at any one point in time, so those on older systems do not need to fear the zombie plague destroying their computers before even reaching their homes.
Altogether, there are almost no real negatives to dealing with this zombie apocalypse. While it can make the game much harder, the increased challenge is purely skill-based; it's built around managing the hordes through footwork or base defenses rather than providing a simple statistical improvement to the enemy.
Those with the capability to keep track of multiple enemies and who are careful enough to not leave areas around their homes where the undead can swarm in from will find the mod's changes to simply add a nice bit of spice to their game. And thanks to the impressive configuration files, players can easily set the mod up to only improve the undead's intelligence, supply that extra brainpower to additional monster types, or disable any part of the mod that the find issues with.
Zombie Awareness may only change a relatively small part of the game, but it brings a sense of danger to Minecraft that many players have not felt since their very first night.