- "Trade speed for power—shift biomass to your forearms to allow deadly area-effect attacks, crush guarding enemies, and shatter armored vehicles. Hammerfist delivers the pain."
James Heller also acquired his Hammerfists after consuming the DNA of a variant of Juggernaut which was able to create groundspikes. Heller was capable of devastator attacks with Hammerfist's effects and creating groundspikes similar to Mercer's Claws.
- "Blast enemies out of your path with this powerful combo. It is slow, but powerful- especially effective against enemy armor. Be wary of using against faster opponents."
Hammerfist Smackdown, the first upgrade for the Hammerfists, is a slow but highly damaging slam attack. Alex starts to grow his Hammerfist on a higher size and the top of his hand is heavy enough to make a shockwave. Then he proceed to smack downward to make a bigger shockwave, doing the second attack makes Alex almost lose his balance. Capable of destroying early armored vehicles with a single direct hit, but at the cost of attack speed. While charging the power, Mercer is susceptible to being interrupted by attacks. Otherwise, a fully charged attack has the effect of delivering two shocks upon anything within range.
Hammerfist Elbow Slam
- "Jump up, drop down. Deadly against armor. Add extra height to increase your damage and area of effect. With the right conditions, you can crack an enemy Tank with a single blow."
Hammerfist Elbow Slam is the second upgrade of Hammerfist. It is essentially the normal elbow slam maneuver with the upside of increased damage and area of effect, as well as not requiring the running up of a wall to execute. Like the Hammerfist Smackdown, this move can help in destroying armored vehicles and Hunters. In order to use this power, the Prototypes will have to gain some altitude, before dropping down on an enemy with a deadly force. The higher the altitude and attack charge, the more damaging the attack.
- "Sprint into a self-throw and put all your weight into a single, concentrated attack. The Hammertoss is dangerous when you miss—and deadly when you hit."
Hammertoss is the final upgrade for the Hammerfist. This upgrade helps to deal with airborne enemies, like the Gunships and UAVs to a limited extent. It is also a handy way to toss Mercer over obstacles and clear out his landing area of any minor enemies. Ironically, considering that the Hammerfists are slow, the Hammertoss is very good for mobility, clearing an entire street in one fully charged toss.
|Hammerfist Power||Behind the Glass||48,000|
|Hammerfist Smackdown||Behind the Glass||48,000|
|Hammerfist Elbow Slam||Biological Imperative||675,000|
|Hammertoss||Making the Future||900,000|
The Hammerfists are quite capable in anti-vehicle combat, as repeated strikes will lift APCs and tanks off the ground, preventing them from retreating. They are also quite useful against Hunters -- especially Leader Hunters, who will be stunned by the heavy strikes. Even Super Soldiers will quickly enter their blocking stance after sustaining a couple of shockwaves, which Alex can exploit to a grappling advantage.
In close proximity, it can be used to clear large groups of human enemies quickly. If Alex charges up his punch, he can knock one enemy horizontally into another, instantaneously killing both enemies. He can also use a four strike combo that shatters the street and creates a shockwave dealing heavy damage to everything nearby. 
The Hammerfists lack attack speed and are slower than any of his other abilities. Unless Alex strikes point-blank, enemies are liable to move out of range or retaliate before he can get a hit in. Armor, especially when moving, can be difficult to hit unless Alex gets in their path.
Though powerful, the Hammerfists are quickly eclipsed by Alex's other offensive powers in terms of damage over time. Though the Claws are weaker in most respects, Musclemass, the Blade, and even the Whipfist do more damage over longer periods thanks to their greater attack speed. Musclemass, used in conjunction with Alex's various combat moves, will do far more damage over time than the Hammerfists, with the added versatility of enhancing his throwing power.
The Blade will do more damage over time to living enemies than the Hammerfists will, and the Air Blade attack will reliably kill tanks from any height, whereas the Elbow Drop of the Hammerfists needs to be done from a significant height to accomplish the same.
The amount of moves available with the Hammerfists stay the same as in the first game. Heller is able to use Hammerfist combo chain, Hammerfist Groundspike, Hammerfist Elbow Slam and Hammerfist Divebomb.
Hammerfist Elbow Slam is faster to do than the first game. Heller immediately drops to ground from air unlike the first game which Mercer must prepare and charge his elbow to drop. As Mercer can perform Hammerfist Smackdown, Heller has instead gained a new attack, Hammerfist Groundspike. Heller's ability to create Groundspikes stem from the Hammerfists instead of Claws. Holding the attack button will push Heller's hands into the ground, launching up spikes around him. When players are about to perform Hammerfist Elbow Slam, pressing the dashing button when the slam contacts with the target, will damage the opponent and quickly recover from the attack but won't create the shockwave. This strategy can be used for quickly defeating single targets like Brawlers or Tanks as there is no time loss from recovering from the attack. This can be used for Blade Air Slice too.
Heller has a new attack named Hammerfist Divebomb, in which which Heller charges his Hammerfists and dives to the ground, creating a circular shockwave which lifts enemies up and erupts Groundspikes from the ground similar to the Groundspike Graveyard Devastator from the first game. Heller can perform a different version of this attack which while normally spikes erupts from the ground as a circle; in some Radnet events, Heller can erupt spikes in a long straight line. Players cannot do this event specific move in normal gameplay. There are three ways to do this -- when in the air, holding the attack button will propel Heller downwards, fists first, and spikes will plunge upwards around him, in a circle, similar to the Groundspike Graveyard Devastator in Prototype, but smaller. Second, is at the end of the combo (tapping the button), Heller will launch spikes out of the ground, around him in a circle, just like the first method. Third, is to be on the ground, and hold the button. This results in a forward shockwave of spikes, traveling in a single direction.
Upgrades in Prototype 2
- Level 1 - Hammerfists acquired.
- Level 2 - Hammerfists damage radius increased.
- Level 3 - Range and size of Ground Spikes increased.
- Level 4 - 25% boost to Hammerfists attacks.
- When standing still, Alex slumps over and hangs his fists down, hinting at how heavy they are.
- This is the only power that has an idle animation in Prototype. If Alex remains idle for a few seconds, he will beat his fists together.
- This is the only power in Prototype 2 which has a 4-hit combo. Other powers have a 5-hit combo.
- Performing a helicopter finisher with the Hammerfists will result in the same animation as an unarmed finisher.
- Though Mercer's biomass is focused on his hands, he performs an elbow slam. This was probably not taken in mind by the developers when making Prototype 2, hence the fact that Heller can also perform an elbow slam.
- Note that Heller's Hammerfists are shown causing more damage compared to Mercer's. But when upgraded to Level 2, his radius will slightly more increase than Mercer's fully charged Hammerfist attack.
- Though Heller's Hammerfists have greater damage radius, they are not capable of tossing tanks and APC's like Alex Mercer.
- Hammerfists' groundspike stems are greatly crowd controlling but less powerful than Claws' groundspike, which on charging toss the tanks and stun Hunters and larger Infected.
- Alex Mercer still uses his original animations from Prototype when he uses the Hammerfists during Murder Your Maker.
- On an additional note, Alex will perform the Hammertoss move during the final boss fight in Prototype 2. As the attack cannot be blocked, Heller has no choice but to dodge.
- Although the Hammerfists are powerful in Prototype, they are outclassed by the Blade which does their job better and faster.