As the round starts, soldiers have their usual countdown to find any spots to defend before the host infections are chosen. The host mutants won't start with their skill and only have 850 HP, but they have very little knock-back when shot at to balance things out. Much like HMX, they will be dead permanently if killed by any melee weapons.
Both factions now have level meters, which slowly fills up by itself for soldiers, while mutants infect/attack soldiers and/or taking damage or collect crates. Unlike previous modes, mutants get to keep half of their bar upon infected, and they don't lose progress when respawning, but they can't adsorb EXP from dead mutants to evolve. For each completed levels, both will receive many perks; last one being transformation into Knights and Armored Mutants respectively.
|An abandoned fort right in the middle of the desert.||A small set of mystical islands during the night.|
|Popular Hero X map set at a summer resort.||Ruin site that is located deep into the jungle.|
- Unique to all other modes, Mutants can earn progress via succeed hit (Even if they can't infect soldier due to Mutation Armor). This makes them very dangerous in CQB even if they are flashing red - getting one hit may instantly bump their HP back up and give them the chance to infect soldiers.
- The Armored Mutant in the Mutation Knight Mode made his first appearance in Thunder Tower as a re-textured version of the normal mutant zombie.
- It's rumored that the automatic Knight transformation for soldiers was meant to prevent them for farming points by shooting mutants, since in Hero Mode X soldiers had the choice to turn into the Commando / Ranger or not and still was able to shoot more points. Now, they are forced to actually fight the mutants heads-on after their maximum level is reached. This doesn't prevent them from using Mounted FAL Camo however (Desert Fortress), but at least mutants have more chance to get to them.
|Soldiers damage increases.||Mutant health point increases.|
|Additional mag(s) for primary guns.||Mutant Health Regen ability.|
|Heartbeat Sensor Activation||Thermal vision ability activation.|
Heartbeat Sensors, unlocked at level 2, will highlight part of soldier radars, in a cone-shaped form, every few seconds in the direction they are facing. Any mutants that is found within the range of the sensor will be exposed on soldier radars.
Thermal Vision, tied to health regeneration, allows the mutants to see through walls and perfectly locate soldiers as they will be highlighted in white as long the mutants do not move away from their current positions. Both of these abilities are unlocked once their first level is completed.
|G-Skills||Mutants respective skills; Armored Mutants use Xeno's forcefield.|
|Roar||A roar that impose fear, which freezes and disarms nearby soldiers.|
|Heat Signature||When standing for 3 seconds, all soldiers will be high lighted in white color for the user.|
Supply crates are still present in this variation and are more valuable than ever before as it contains some goodies that can most definitely save a soldier's lives and possibly other's.
Although, unlike in previous variants, there are no weapons crate, preventing soldiers from losing their equipped weapons. The items available in these boxes are as follows:
- Shock Grenade: Creates a large electrical sphere that slow down mutants inside it.
- Ammunition Refill: A complete refill of a soldier's ammunition of his primary weapon.
- Mutation Jacket: Allows additional hit(s) before getting infected; stack-able to three.
- Gauge Increase: Mutants are now able to collect crates, boosting their level gauge.