Video Game / Entropy : Zero 2

Bad Cop is back.

Unit 3650, you are tasked with directives:
Intercept malignant agent Judith Mossman. Code: clamp, contain.
Investigate and report non-patrol region.
Failure to comply will result in perk termination.

Entropy : Zero 2 is a modification for Half-Life 2 created by Breadmen, a developer team headed by Breadman, the creator of the original Entropy : Zero, and released on Steam on August 20th, 2022.

This sequel once again follows the wise-cracking sociopath Bad Cop — more precisely, the last of the Overwatch soldiers copied from Bad Cop after his consciousness was uploaded to the Combine's repository at the end of the original mod. After awakening in the ruins of Nova Prospekt, he's briefed by a Combine Advisor on the current state of affairs: the Administrator is dead, and the Combine on Earth has been cut off from the Overworld. The Advisor then gives Bad Cop new orders to capture Judith Mossman, the double agent who helped undermine the Combine's grasp on the planet, and uncover the secret project she and her team were trying to find. With this, Bad Cop falls in with an Overwatch regiment heading north to track down Mossman at the Arbeit Communications facility, showing no mercy to the rebel and alien forces who stand in the way of his goals.

The threats Bad Cop faces on his latest assignment are greater than ever, but this time he's not alone. He's got a team of Overwatch soldiers at his disposal that he can command in the same vein as Gordon and his squad of Resistance fighters in Half-Life 2, as well as a plucky sidekick in the form of a defective turret named Wilson, who can be used to open up hidden supply caches and, in a pinch, serve as a bullet shield. He does, on the other hand, have a bigger adversary to worry about, as it's soon made clear that he isn't actually the last of his copies, nor was he the first to be sent north to confront the Resistance...

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Entropy : Zero 2 contains examples of:

• 11th-Hour Superpower: The prototype AR2 from the first Entropy : Zero makes its return just after the boss battle in the Entropic Control facility. Its devastating stopping power makes it a useful weapon for the remaining fights.
• All for Nothing: This is what the best ending details if Bad Cop denies the Advisor from wiping his memories, with Bad Cop shouting this to the bastardly, uncaring Advisor that informs him that it will soon wipe his memory so that the clones after him are perfectly obedient with following orders blindly.
  Bad Cop: I GAVE EVERYTHING FOR YOU!
• All There in the Manual: Has an external lore dump just like the first Entropy : Zero in the form of the Arbeit Communications Comms.
• Anti-Frustration Features:
  • During "Venture Ghost", should you somehow lose your APC, Bad Cop will sheepishly request a replacement from Overwatch.
  • Multiple conveniences are made so that you don't have to bring Wilson with you (or are made aware, at least, that you don't need to) when you're inevitably going to backtrack, such as a weight-limited elevator or supply closets he can't open immediately. In a similar vein, payload transport platforms are available to transport him to a spot further along so that you don't need to lug him around during intense firefights or up ladders.
  • Wilson is also impervious to Xen Grenades. If he's sucked in by one, he'll just pop right back out.
  • A radar shows which direction Wilson is, allowing the player to find him more easily should they get separated.
  • Rebels can now throw grenades. To ensure that you don't mistake them for your allies' grenades in the heat of combat, the trailing light on rebel grenades is coloured yellow. The same goes for whenever rebel snipers appear; their laser sight is colored yellow as well.
  • Judith Mossman, who is needed alive, is immune to certain weapons and also tougher to kill when there are enemies around, possibly to prevent accidentally killing her.
  • Unlike most other HL2 mods out there in which rebels would constantly switch to weaker vanilla weapons when they had a much better mod-implemented weapon beforehand, in EZ2 your fellow Overwatch soldiers hold on to their current weapon indefinitely, and you can personally choose which weapon you want them to wield by holding it in front of them. After a moment or so, they'll drop the weapon they were using and will grab the one you've offered instead.
• Apocalyptic Log: Several audio recordings created by Clone Cop can be found in Arbeit 1 which detail how he was left for dead by the Overwatch dispatcher and subsequently trapped in the Arbeit labs. A few others, recorded by Radio Guy, reference a Combine soldier he and his colleagues managed to capture.
• Awesome Personnel Carrier: Bad Cop is given his own Combine APC by Overwatch at the beginning of "Venture Ghost". While it can't carry other squadmates within it, Wilson can be mounted in the back to make carting him around the wastes much easier.
• Back for the Finale: If Scar Zero is kept alive and escorted as far as possible through Arbeit 1, he returns to help out in the final Hold the Line battle before reaching the Borealis, netting you the achievement named after him.
• The Bad Guy Wins: Regardless of which ending you get, the Arbeit conflict ends with the Combine indisputably victorious. However, Gordon Freeman is not far behind, and in both variants of the "There Will Be Pain" ending, the Combine fail to recover the Borealis, and in the good version, they've made an enemy of a very pissed off Bad Cop who is now being aided by the newly-uploaded Wilson, who has infiltrated the Combine network.
• Bottomless Magazines: The Gauss Pistol, which uses infinitely regenerating ammo.
• Blasting It Out of Their Hands: Or rather, kicking it out of their hands. Rebels who are disarmed this way can be forced to surrender.
• Brick Joke:
  • In the prologue, one of Bad Cop's colleagues screws up the targeting mechanisms of a Manhack, causing it to fly into a nearby vent. When Bad Cop is crawling through the vents sometime later to exterminate the headcrabs nesting inside, the same Manhack pops out from a nearby shaft and attacks him.
  • In a conversation with Wilson, Bad Cop will mention that he can't feel anything from his waist down. Later on, once Bad Cop makes contact with a Xen Healing Pool, he will gleefully exclaim that he can feel his legs again.
• The Bus Came Back: Several creatures from Half-Life and its expansions make their return here after being absent from Half-Life 2, including Bullsquids, Pit Drones, Gonomes, and Xen Trees.
• Call-Back:
  • The tripmine-rigged room in the first Arbeit facility harkens back to similar scenarios found in the Half-Life series proper. Also, after getting past most of the tripmines, a rebel throws a grenade through a high-up opening in the wall, referencing a scene from the original Entropy : Zero.
  • Clone Cop ends up inadvertently quoting the G-Man when Bad Cop refuses to work together.
    Clone Cop: "Well, it looks like we won't be working together..."
  • Nearly all of the Aperture test chambers hidden beneath the Arbeit facilities utilise the original Portal's Aperture aesthetic.
  • "Chamber Catacomb" has you hiding from a Gonome and avoiding making noise lest you attract its attention, not unlike with Jeff in Half-Life: Alyx.
  • The cabin that Bad Cop comes across during "Exhumation Zone", described by Wilson as having belonged to the CEO, features a large portrait of Cave Johnson above the fireplace.
  • The Xentarium (besides being thoroughly overrun with Xenian flora & fauna) is being assailed by a pit drone army, who have invaded by a series of purple portals that are essentially miniaturised versions of the Gene Worm's portal.
  • Chapter 5, aside from being named "Apprehension" just like a similar chapter in the first Half-Life, opens up with the Combine's perspective of Mossman's message from Episode One, including the Hunter attack. It can also be seen as a nod to Opposing Force's "We Are Not Alone", which also shows a familiar scene from the point of view of a "bad guy."
  • The scene where Mossman discovers Bad Cop in the Arbeit 3 airlock plays out almost exactly like the Black Mesa East airlock scene in Half-Life 2.
  • Behind one of the doors leading to the satellite comms facility is a group of four Aperture turrets lined up like the turret quartet in the ending of Portal 2. In this case, though, they're only interested in serenading you with bullets.
  • Bad Cop runs into a gun emplacement while he's right on Mossman's tail, at which he exclaims "A manned gun! My old nemesis!" One of the most notorious encounters from the original mod was a gun emplacement sticking out of a wall at the end of a narrow hallway.
  • The names of the achievements granted for the two different endings reference the Advisor's parting words to Bad Cop from the previous installment: "There will be pain, and then there will be darkness. We will see you up ahead."
• Canon Immigrant:
  • invoked One of the enemies that can pop up from the Xen Grenades are HEV Zombies; a Recurring Fanon Character appearing in several other mods such Field Intensity and Half Life Zombie Edition, though the garbled HEV Suit voice sounds they produce are evidently meant to evoke their Black Mesa incarnation. Curiously, Entropy : Zero 2's HEV Zombies sport a suit more visually similar to Gordon's Mark V HEV Suit, rather than the original Mark IV Suit seen in Half-Life.
  • Stukabats, cut enemies from the Half-Life 1 beta, can also pop up from the Xen Grenades in certain areas of the mod.
• Can't Kill You, Still Need You: You can slaughter the Resistance medics like any other enemy, or detain them and force them to heal you, granting you the "Interdependency" achievement in the process.
• Challenge Run: Similar to the Advanced Test Chambers in Portal, bonus levels are provided in which you have to run through a single map fulfilling one of several challenges: Least Damage, Least Kills, Least Time, Least Bullets, or Most Mass (absorbed with Xen Grenades).
• Chase Scene: One with the Gonome lurking in the Arbeit secret labs during "Chamber Catacomb", and another with Clone Cop while you're escorting Mossman to safety.
• Color Motifs: Red for Bad Cop and the Combine, blue for Clone Cop, and yellow for the Resistance.
• Continuity Cavalcade: The introduction of the Xen Grenades is this, with Hazardous Environments (arguably the most recognizable Half-Life 1 song) playing as you see iconic elements, such as enemies and HEV batteries, from the first Half-Life pop out from the Xen portals created by the grenade.
• Covert Group with Mundane Front: Through a partnership with Aperture Science formed sometime before the Black Mesa incident, Arbeit Communications would go on to become a front for Aperture's research in the Arctic.
• Cowardly Mooks: Rebel enemies may drop their weapons and try to flee if their "willpower" level is sufficiently low, giving you an opening to rush in and detain them.
• Creator Cameo: All of the Metrocops in the prologue are voiced by Breadmen developers and playtesters.
• Developer's Foresight:
  • There's a unique exchange between Bad Cop and Wilson in the event the latter hurts the former via physics damage.
    Bad Cop: Aargh! For fuck's sake!
    Wilson: Sorry.
  • Bad Cop also has a unique response if you play the mod with God Mode.
  • Should you bring Wilson to the top of the Arbeit control tower where you confront Judith (instead of leaving him at the locked supply closet just before reaching it), some extra dialogue between Bad Cop and Clone Cop plays out.
  • During "Contact Aberration", on the off chance that you backtrack all the way to the courtyard after reaching the warehouse, you'll be met with a pack of Bullsquids who have taken to feasting on the rebels you killed earlier.
  • If you're quick enough to shoot the rebel who throws a Molotov to burn a pile of research materials, the Molotov will explode in his hand and set him and his nearby friends on fire.
  • The developers counted on players trying to stay right on Mossman's tail during the chase leading to the Satellite Comms facility and placed a teleportation effect to justify her sudden disappearance before the level change.
• Dialog During Gameplay: Bad Cop will occasionally engage in conversation with Wilson while carrying him around. Their discussions start out apprehensive, but eventually, Bad Cop opens up about his past and they come to understand each other more.
• Diegetic Interface: The Left 4 Dead-style tooltips are seemingly justified as being part of Bad Cop's Combine augmentation, as they're also used to relay orders and information about his objectives.
• Dismissive Kick: In the "There Will Be Pain" route, you can kick the G-Man out of spite rather than listen to what he has to say, causing him to dispose of you by dropping you into a pit with a Gonome and no weapons.
• Early-Bird Cameo: The image of a mysterious Combine Elite can be seen flashing briefly on the monitors around the Arbeit 1 warehouse. Said Elite is Clone Cop, who gets introduced to the very next level.
• Earn Your Happy Ending: You're guaranteed to land in a Downer Ending of some capacity unless you go to the trouble of taking Wilson all the way to the AI upload station. Carrying him around is less frustrating than doing the same with the Gnome in Episode Two, as he can be attached to the roof of Bad Cop's APC (no such accommodation existed with the Gnome and the Muscle Car) and can unlock otherwise inaccessible supply caches all throughout the Arbeit complex, but an extra amount of effort is still required to lug him around and make sure you don't lose him or let him get destroyed. Even after getting Wilson to the upload station, you'll have to endure one last boss fight against the Advisor to get that good ending.
• Eerie Arctic Research Station: Parts of the Arbeit complex are very hazardous, spooky, or both.
• Elite Mooks:
  • Along with the standard Resistance fighters there are Brutes, who wield shotguns, fight more aggressively, and can tank headshots thanks to their welding masks, and Jumpers, who can jump long distances and are generally extremely mobile.
  • The Gonomes from Half-Life: Opposing Force make a return here. As usual, they're stronger, faster and far tankier than your average Headcrab Zombie. One of them even serves as the Arc Villain for the chapter "Chamber Catacomb."
  • Also joining the lines of the Headcrab Zombies is the "Zombiegaunt," an offshoot of Episode One's Zombines. They're capable of doing what a regular Vort can, with the addition of being passive to the Zombie faction and keeping their smarter pathfinding in contrast with their peers.
• Enemy Mine: Bad Cop can form a tenuous truce with the Vortigaunts if he uses Xen Grenades to summon them during the Advisor boss battle. If Bad Cop talks with them afterwards, they reassure him of their newfound alliance but make it clear he isn't forgiven for murdering their kin in the past.
• Equivalent Exchange: The sizes of enemies spawned by the Xen Grenades are directly proportional to the mass of what the grenades suck up. Absorbing small props may spawn a few headcrabs and zombies, for instance, while larger objects like cars can summon Antlion Guards in exchange.
• Expy: Temporal Crabs are these to the Revivers from Half-Life: Alyx. They're both blue, around the size of a headcrab, have the ability to vanish and reappear elsewhere, appear in only a few encounters, and are significantly hardier than your typical cat-sized Xen creature.
• Faustian Rebellion: If you so choose. In the final chapter of the mod, the Advisor instructs you to surrender your consciousness, submit to a total memory wipe, and become the template for a clone army of Overwatch soldiers. You're prompted to comply, but can refuse this and shoot the Advisor in the face, thus initiating a boss battle and the "There Will Be Pain" ending.
• Fiery Cover Up: Beneath Arbeit 2 you'll run into a group of rebels who are trying to destroy their research by burning it. Bad Cop is quick to remind them that "arson is illegal".
• Freeze-Frame Bonus: During the "There Will Be Darkness" ending, Wilson's eye can briefly be seen on one of the Combine monitors if you put him in the upload station.
• Gameplay and Story Integration: During the "There Will Be Darkness" ending, once Bad Cop loses his faculties and memories, while the player still sees from his perspective, he can no longer be controlled from that point onward, demonstrating that he is now nothing but a functionally living drone controlled by the Combine. This also means he becomes easy pickings for Gordon Freeman, whereas previously he was one of the few people in the setting possibly capable of taking him on.
• Grim Up North: The Arctic happens to be flush with alien wildlife that hasn't been seen since the Black Mesa incident.
• He Was Right There All Along: That huge mass of shipping crates floating over your head as you finally come face-to-face with Clone Cop? The Advisor is hiding inside of it.
• Helpless Window Death: Once Bad Cop has Mossman cornered in the Arbeit control tower's transmission room, a squad of Combine soldiers shows up to unlock the doors and extract them. Clone Cop drops in not a moment later and kills the entire squad while his newer copy can only watch on through the bulletproof window.
• Hilarious Outtakes: A bunch of blooper lines are included in the game files, right alongside the finalized ones.
• Hold the Line: One against a rebel platoon that assaults Bad Cop and his team at the Arbeit executive lodge, a second in the warehouse at the Satellite Comms facility while waiting for a Combine cutter device to breach the warehouse doors, and a final one while waiting for a cargo mover that will take Bad Cop to the project's location, with an army of rebels making one last desperate attempt to stop him.
• Idiosyncratic Difficulty Levels: Similar to the original mod:
  • Metrocop: Shoot because you feel like it.
  • Combine Soldier: Shoot to win.
  • Combine Elite: Shoot to survive.
• I Know Your True Name: Unsurprisingly, G-Man is fully aware of Bad Cop's original true name.
  G-Man: You don't belong here... Mister Walker.
• Infodump:
  • A lengthy slideshow presentation in the Arbeit underground labs provides in-depth explanations of the temporal phenomena Arbeit and Aperture were studying.
  • In the first chapter, Bad Cop's previously undisclosed backstory is revealed all at once through one of his co-workers reading his Civil Protection profile out loud.
• Interquel: The majority of the action is set between the ending of Half-Life 2 and the beginning of Episode One.
• Ironic Echo: Realizing that his disparaging lectures aren't getting through to Bad Cop, Clone Cop doesn't hesitate to throw his words about their status as esteemed Combine units back at him.
  Clone Cop: You know, everything belongs to them.
  Bad Cop: Well, yeah. We gave everything for this privilege.
  (a short time later, as the two are talking face-to-face)
  Clone Cop: I'm done trying to resolve your past. I'm done with my life.
  Bad Cop: It's our past!
  Clone Cop: No. You gave everything for this privilege, remember?
• I Surrender, Suckers: Don't think just because you've disarmed and detained rebels, that they're no longer a threat to you. Once your back is turned, they'll very likely get back up, grab any loose weaponry lying around, and open fire. You'll need the assistance of other Combine units to keep them locked down.
• Leaning on the Fourth Wall: After passing through a makeshift research station underneath Arbeit 2, it's possible to backtrack and meet with a Combine squad who come onto the scene to investigate the area. Interacting with them will cause Bad Cop to accuse them of "just acting busy" and not doing actual work. Sure enough, a glance at the level in the Hammer editor reveals their evidence-gathering routines are controlled by the Actbusy system.
• Meaningless Villain Victory: What the Wilson ending and G-Man ending amount to. The Combine capture the Arbeit facility and arrest Judith Mossman, but fail their overarching objective. They don't recover the Borealis, with the ship apparently being seized by the G-Man's employers. There also don't seem to be any portal guns anywhere in the facility, and the Combine have no use for the Xen grenades, which makes yet another failed Combine mission to find the teleportation technology they're so desperate for.
• Medium Awareness: The caution signs that state "Absolutely no level transitions at any time". There's even an "X days without a transition" sign that changes its day count from 52 to 0 after a level change.
• Mêlée à Trois: The story is centred around a three-way conflict between the Combine, the Resistance, and Clone Cop. You can also invoke this during any given battle using the Xen Grenades, which have the side effect of spawning in alien lifeforms with each use.
• Mirror Boss: During his Boss Battle Clone Cop fights much like the player; using strafing, ambushes, and a variety of firearms to hold his own against Bad Cop.
• Multiple Endings:
  • "There Will Be Pain": Bad Cop defies the Advisor, kills it, and then boards the Borealis after activating the bootstrap device. He then encounters the G-Man on the bow of the now-seized ship, who in exchange for his work in stopping the City 10 uprising during the previous installment, allows him to destroy his own imprint in the Combine's mind repository, preventing them from ever making more copies of him. This ultimately falls through, as the Combine manage to overpower the G-Man and capture Bad Cop in an attempt to use him as a template once more...
    • That is, unless you put Wilson in the upload station, in which case he rescues Bad Cop and the two set off to stop the Combine from taking the Borealis.
  • "There Will Be Darkness": Bad Cop doesn't resist the Advisor relieving him of his memories, proceeding afterwards to assist the Combine in securing the Borealis. The Resistance storms the Borealis just as Mossman is being led onto the ship, and Bad Cop gets cornered and killed by Gordon and Dog.
• Mythology Gag: Arbeit Communications borrows its name and logo from Arbeit Laboratories, an organization alluded to in a placeholder texture found in the Half-Life 2 leak.
• New Weapon Target Range: The rooms following where you first pick up the Xen Grenades are occupied by zombies you can test the grenades on. There's also a weighted cube on the other side of a door, with it being held shut by a button the cube is resting on. The cube can only be removed by throwing a Xen Grenade into an opening above the door.
• No-Gear Level: Bad Cop’s arsenal is destroyed by an emancipation grid at the beginning of "Chamber Catacomb", leaving him without weapons (aside from his boot) to fight off the creatures infesting the abandoned Arbeit test chambers, including the resident Gonome, until he comes across some supplies in Clone Cop’s hideout.
• Non Standard Gameover: As per Half-Life tradition, letting important people die or making poor judgements will lead to an early game over. Examples include:
  • Running outside the elevator to exit Arbeit 1 will cause it to lock you out, with an Overwatch message that the elevator buttons stopped working for some reason.
  • If the player jumps into a certain dumpster outside Arbeit 2, they'll be unable to climb out. The screen then fades to black and says "The rebels have bested you."
  • Letting Wilson die before you leave the Arbeit facilities, which leads Overwatch to remark on Bad Cop's Host Body rotting due to lack of sustainment.
  • Killing too many friendly Combine soldiers, leading Overwatch to remark on Bad Cop being too unstable and disposing of all his clones.
  • Letting Mossman die, leading Bad Cop to gloat about her death before realizing he screwed over his entire mission, and leading Overwatch to retract his Family Cohesion perk.
  • Lastly, Bad Cop can also refuse G-Man's offer by kicking him at any point during the "There Will Be Pain" ending, leading G-Man to drop you in a cave with an angry Gonome and letting you die.
• Optional Party Member:
  • Scar Zero, an Overwatch soldier who's been tortured half to death by the Resistance in the Arbeit 1 warehouse. It's entirely possible to not even come across him during a playthrough, especially if you don't have any SLAM mines to destroy the wall blocking your way to him.
  • Wilson only has to be carried around for the duration of "Chamber Catacomb", and you're able to abandon him after leaving the Arbeit 1 labs without consequence. Should you bring him along afterwards, however, you'll gain his eternal gratitude, a means to unlock the otherwise inaccessible supply caches located throughout Arbeit, and a much more optimistic outcome to the "There Will Be Pain" ending if you bring him all the way to the AI upload station in the final chapter.
• Pensieve Flashback: Temporal overlays, an anomaly that allows Bad Cop to observe past (and possibly future) events due to temporal disturbances.
• Perspective Flip: The Combine invasion of the Resistance’s arctic stronghold, previously only seen from the perspective of Mossman’s video message in the Half-Life 2 Episodes, is now shown from the Combine’s point of view, including the moment Mossman is interrupted while recording said video.
• Previous Player-Character Cameo: An easily missable temporal overlay in the Arbeit monitoring station features none other than Gordon Freeman. He also shows up in the "There Will Be Darkness" ending, where he and Dog spring an ambush on the Borealis and kill Bad Cop. While Gordon is never seen directly here, the effects of his Gravity Gun are clear as day.
• Quick Melee: In lieu of any proper melee weapons (outside of the Stunstick in the prologue), there’s now a dedicated "kick" button. It works on enemies, supply crates, and doors alike.
• Rapid Aging: One of the anomalies Bad Cop encounters on his journey causes pockets of space to rapidly increase the passage of time of anything that touches them. Living beings that come into contact with these pockets either turn into skeletons or vaporize on the spot, while non-organic items will quickly deteriorate and lose their integrity.
  Bad Cop: Great, now time itself is trying to kill me.
• Remixed Level: The first chapter is set in the ruins of Nova Prospekt, the prison featured in both Half-Life 2 and the ending cutscene of the original Entropy : Zero.
• Shout-Out:
  • Bad Cop frequently references pop culture in his quips.
    • When killing Fast Zombies: "You're too slow!"
    • As he racks up a kill with the APC's rocket launcher: "Say hello to my little friend!"
    • If he kills an enemy with explosives: "They'll be burying what's left of you in a soup can!"
    • If facing off against a lot of enemies: "Oh boy, here I go killing again!"
    • If a grenade lands near him while his health is low: "Heh heh heh... I'm in danger!"
    • When getting shot: "Argh! You made me bleed my own blood!"
    • If he takes fall damage: "Argh! My leg!"
    • If he sets an enemy on fire: "Burn baby burn!"
    • When crawling through an Air-Vent Passageway in the prologue: "Ugh, I feel like a TV dinner."
    • When he finds a Magnum in Clone Cop's hideout: "Wow, a gun! Hell's horses! I wonder if it's loaded." *click* *click* *click*
    • If he tries to get into Clone Cop's supply stash without the equipment needed to Shoot Out the Lock: "Let me in! LET ME IIIIIIIIIIN!"
    • If Wilson gets destroyed while his relationship with Bad Cop isn't strong: "Oh no! Anyway..."
    • If Wilson and Bad Cop's relationship is stronger when the former is destroyed: "Wilson? Wilson! WILSOOOOOON!"
    • When Wilson refuses to tell him classified information: "Fine. Keep your secrets."
    • When killing enemies teleported in by Xen Grenades: "Welcome to Earth!"
  • Some of the achievement names are references too, including"Overwatch Says Stop Kicking It"^note kick the Advisor at the end, "Dirty Harry" ^note kill 18 rebels with the Magnum, and "Now there are two of them!" ^note kill the two Gonomes in the Xentarium.
  • Using the Xen Grenade to absorb skeletons summons floating, flaming skulls with spines that relentlessly charge at enemies while screaming. Killing one can net a unique quote from Bad Cop:
    Bad Cop: Rip & tear, bitches!
  • The aforementioned "acting busy" gag doubles as a reference to Freeman's Mind.
• Spiritual Antithesis: The similarities to Hunt Down the Freeman haven't gone unnoticed by fans. Both games are about being in the shoes of one of the enemy soldiers you gun down by the dozen in the Half-Life series, the plots of both involve hunting down a major character from the Half-Life canon, and both plots run concurrently with the original games' plots. However:
  • Whereas Mitchell is driven forward by a petty revenge quest which ends with him getting double-crossed by the G-Man and killing one of his closest friends, Bad Cop is instead motivated by the prospect of finding his missing daughter and can end up gaining a new friend and getting help from the G-Man.
  • Mitchell's mission to hunt down Gordon Freeman is ultimately a farce, as it was his acquaintance Adam who really beat him into unconsciousness at Black Mesa and he never actually confronts the real Gordon but Bad Cop succeeds in capturing Judith Mossman.
  • While Hunt Down the Freeman has a price, both chapters of Entropy : Zero are free.
• Squad Controls: Much like Gordon and the rebels under his command, Bad Cop can order around a squad of Combine Overwatch soldiers. The main differences here are that the soldiers will wait wherever they're told to indefinitely instead of returning to you after a short while, soldiers can be added to or removed from your squad with the Use key, and the Arbitrary Headcount Limit of four squad members from Half-Life 2 is removed.
• Technicolor Toxin: Biotic cohesion gel, a glowing blue goo made of modified phytoplankton. It seems to be rather selective in what it causes harm to, as certain zombies are soaked in the stuff and become a lot stronger, while other times anything that falls into it dies a swift death. "Plan B" is soaked in cohesion gel, and it's incredibly durable; attempting to kick it actually damages Bad Cop instead.
• Teleport Spam: The Temporal Crab teleports frequently to avoid getting hit, as does Clone Cop during his boss battle.
• Title Drop: In a Call-Back to the original mod, once the Entropic Control reactor is stabilized following Clone Cop's attempt to override it, the AI announcer declares "Core entropy: zero".
• Trash Landing: During "Venture Ghost", while up on a certain catwalk with no way down but to jump, you can aim for an open dumpster below to break your fall. The mod even provides a tooltip encouraging you to "dumpster dive".
• Trial by Friendly Fire:
  • Bad Cop orders canister barrages directly on his position when overwhelmed by the Resistance on two occasions. The canisters will naturally kill him if they land on him, but their impact zones are marked with red bullseyes, making it easy to avoid standing where they're about to hit.
  • If Wilson is present during the battle against Clone Cop, he ends up teleported inside the Borealis alongside him during the final phase. At this point, you have no other option but to shoot the explosive barrels next to them, which defeats Clone Cop but also damages Wilson beyond repair.
• Unique Enemy: There are only two rebel snipers in the entire mod, both of whom show up in the Arbeit 1 warehouse.
• Unusable Enemy Equipment:
  • The USP Match pistol is only useable in the prologue. It's used by the Resistance as a sidearm in subsequent chapters, but can only be picked up as ammo for your MP5K. Similarly, some rebels can use a crowbar as a melee weapon after you kick their primary weapon out of their hands. Should you attempt to grab it, Bad Cop will refuse and say that it's "worthless".^note However, if you start a new game from "Contact Aberration" and manage to avoid picking up the Gauss pistol, you can pick up either the USP or crowbar from a disarmed rebel and keep it until you lose your arsenal in the next chapter.
  • Some rebels use the Counter-Strike: Source Glock pistol as a sidearm. Unlike the USP or crowbar, you can't pick it up no matter what.
• Villain Decay: The Vortigaunts were elite enemies in the previous entry, not to mention a powerful antagonist group who were a key factor in the Resistance’s control of City 10. Here, they’re little more than cannon fodder found among the ranks of the rebels defending the Arbeit facilities, as well as the occasional victim teleported to Earth by the Xen Grenades.
• Weaponized Teleportation: The Xen Grenades, which create a vacuum upon detonation that sucks in anything nearby and teleports it to the Borderworld. Each use of the grenade is guaranteed to teleport things from Xen to your position, whether they be supplies or alien creatures, so it should be used carefully.
• X Days Since: In addition to the self-aware level transition sign, there's also a sign that reads "This job has worked [0] days without a Combine invasion".

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