Chaos Heat is an action game made by Taito and released in October 1998, following an arcade-style Run-and-Gun format where your onscreen character(s) runs around shooting at everything until there's nothing else to shoot at, in an open-world format.
In a Tokyo biolab, an outbreak from a virus strain has resulted in giant, mutated monstrosities being spawned at an alarming pace, with the lab's personnel slaughtered by the creatures before the entire facility goes into lockdown. To contain the mutation from spreading into the city, it's up to a trio elite commandoes in the DEF, each with their own special abilities executed by holding down the firing button long enough, which the player controls to infiltrate the lab and take on the monsters:
Interestingly enough, the game managed to spawn a sequel, Chaos Break (despite ending on a haunting note that couldn't possibly have room for onenote ), which was released in January 2000, but it is a Survival Horror game in the style of Resident Evil and Dino Crisis instead of an arcade-style shooter.
The Heat is on!
- Airborne Mooks: Flying mutant monsters with bat-like wings appears in outdoor areas. And there's a King Mook flying mutant who's a scaled-up version of the smaller flying mooks serving as a boss.
- And Then John Was a Zombie: How the game normally ends: in the final cutscene, after destroying the last mutated monster, your character then boards an evac chopper, having a conversation with a Red Shirt. Cue a Reaction Shot of the redshirt seeing something horrifying, before cutting back to your character — now a mutant monster yourself, having been infected during your escape. Then Roll Credits. A good ending in which this doesn't happen exists, which occurs if you manage to destroy 90% or more of all Chaos Cores spawned by killed enemies.
- Attack of the Monster Appendage: The boss in the laboratory, a set of four gigantic arachnid-like legs suddenly sticking out a grate to attack. You shoot at until its health is spent, whereupon the legs then retreat back into the hole whence it came.
- Bandaged Face: For some reasons unexplained throughout the game, the third playable character, Vogt, has his face entirely obscured by bandages, but not the rest of his body.
- Battle Amongst the Flames: One area is set near a downed helicopter. While your character fends off mutants, the heli explodes and sets most of the area alight.
- Big Creepy-Crawlies: Most of the mutation strain seems to affect insects in the facility, turning them into oversized monstrosities, and you'll be battling giant bugs constantly throughout.
- Body Armor as Hit Points: Collecting Bulletproof Vests extends your life meter by more than half.
- Body of Bodies: Several of the bosses are just multiple carcasses of both humans, animals and machines, stitched together by the mutation. The "Prototype" notably seems to be at least five different bodies stitched into one, and a later boss is a set of humanoid lungs with a serpentine neck and waddling on spider-legs, at least one which is a human's.
- Brain Monster: One such monster appears in the lab, as a gigantic brain growing out a pool. With neural veins sticking out the water's edges, having two muscular clawed arms capable of slashing at you and a single eye growing in its center. It's also one of the longest boss fights since you need to kill it three times.
- Combat Tentacles: On several of the bosses. The "Prototype" notably has one in place of its left hand which it'll use for whipping at you from a distance, the Brain Monster in the lab has tentacled barbs growing from its sides in the second and third phase of its boss fight, while the Final Boss mutant core's last form is a giant pulsating heart with protruding tentacles it will use during battle.
- Crate Expectations: Plenty of craters shows up in various areas, for the player to smash open for points and weapons. Including areas unlikely to contain crates — while finding them in warehouses and loading bays are expected, you can find crates in an office's conference room...
- Die, Chair, Die!: In-between killing assorted mutant monstrosities, you can destroy pretty much every single interior furnishings for points and bonuses, including chairs, tables, water-coolers, potted plants, cabinets, fire extinguishers, and as always blowing up random objects will drop items for point.
- Elevator Action Sequence: The second boss. You managed to escape into an elevator and travel up, only for a mutant abomination with spider-legs growing out its back to drop from the ceiling. Cue a boss fight as the elevator continues going up.
- Faceless Eye: How the Final Boss reveals itself. As the mutant core comes into view, it starts off as a gigantic floating eyeball who spews Eye Beams all over the place. Once its life is spent though, it shrinks before assimilating into a far more humanoid second form.
- Flower Mouth:
- The first monster boss spawned by the virus from is a massive serpentine creature with a splayed mouth that opens into eight petals.
- The "Prototype" mutant boss has these as well, with a tiny head hidden inside.
- Flunky Boss: Most of the bosses can unleash lower-level mutants as backup.
- The giant serpent mutant can sometimes lunge its head into hitting the ceiling, causing Giant Spider mooks to drop down.
- The giant winged mutant boss, itself a King Mook version of the regular flying mutants, will expectedly dispense its flying underlings during battle.
- The Brain Monster boss from the lab can occasionally summon Living Gasbag enemies as flunkies.
- Foreboding Fleeing Flock: Prior to facing the giant Brain Monster boss, you enter a lab filled with the lowest-level mutant enemies. Who suddenly flees as soon as you're on sight. And then the monster starts rising out the bubbling pool to attack.
- Giant Spider: Several of the mutated monsters take the form of oversized arachnids, from spider-like monstrosities up to your player's waist to being as large as the room they're fought in. The elevator boss battle notably has a King Mook spider animating a corpse to fight as its first phase, before ditching the corpse to continue battling.
- Hellish Copter: Early in the game, you managed to radio in an evac chopper to provide you a lift, only for a bunch of infected monsters suddenly appearing forcing you to take an alternate path. You fought your way to a helipad outside, just in time to see that chopper of yours ambushed by other monsters and crashing — cue the rest of the game where you took the long way upstairs by fighting through multiple levels infested with monsters.
- It Can Think: The mutant growth is assumed to infect only living beings, like the facility's personnel animals in cages. But you can come across machines animated by the mutants as occasional mechanical enemies. There are also zombified, dead security guards who can use firearms on you.
- Laser Hallway: The inner sections of the labs have indestructible laser turrets firing at full-auto, sweeping beams in narrow corridors or walkways, where you'll need to time your run across to avoid getting hit. What's even worse is that mutant enemies tends to appear in these areas, and somehow they're immune to the lasers.
- Living Gasbag: Mutant spores, floating enemies with a single red core in its center surrounded by a fleshy sac full of air. They're an Action Bomb-type enemy who self-destructs into a bunch of projectiles.
- Macross Missile Massacre: All three players can execute a special move that turns their current weapon into a missile launcher that unleashes a whole volley on mutants. And home in on the nearest target for good measure.
- Mutants: Pretty much all the enemies the game throws at you. Most of them resembles insects, albeit deformed and twisted to horrifying proportions, while many of them have fused with dead personnel or animals, or are otherwise growing on machines and driven to attack everything in sight.
- Possessing a Dead Body: The smaller mutant creatures took over corpses of dead research personnel, animating them into attacking the marines.
- Protection Mission: The first stage has a locked area where the only exit is an electronically-locked door where a Red Shirt tries hacking through, just as various mutant monsters bursts out from surrounding vents and attacks from all sides. You'll need to cover him for 30 seconds and fend off the monsters, and if the redshirt dies, you'll need to restart the area.
- Puppeteer Parasite: One of the many infected creatures are parasitic blobs, which attached themselves to corpses of researchers and guards killed during the mutation strain leak animating their corpses (who moves like a zombie) into attacking. In the And Then John Was a Zombie ending, it's revealed in the last minute that your current character is unexpectedly infected by one of these blobs, prior to the credits. Your subsequent fate is unknown.
- Recurring Boss: The "Prototype" mutant monstrosity is initially fought in the room it's created in. After its defeat, it will reappear in the control center, several minutes of gameplay and two other bosses (after the set of tentacles in the lab and the Brain Monster in a pool) later. And then comes back immediately after its second defeat, a third time in the docking bay. Its third form is upgraded with a Spread Shot ability of yellow energy bolts for good measure.
- Redshirt Army: More than one level will throw a handful of marines with you, meant to assist in battling the mutated creatures. They usually don't last the entire area, getting killed by monsters while dealing between minimal to zero casualties on enemies.
- Rodents of Unusual Size: Giant, skinless rat monsters are one of the many hostiles spawned by the bio-lab's viral outbreak.
- Scenery Gorn: Every single interior area, basically, in ruins after a massive mutant outbreak. It's either filled with destroyed machines or facilities or littered with the dead. In either case, it's crawling with assorted monsters.
- Sequential Boss:
- The second boss, a skinless giant humanoid mutant with spider-legs growing out its back, which your character fights in an elevator. Its first form alternates between throttling you from up close or using the spider-like appendages on its back to lash out, until you kill it. But then you're treated to a cutscene where the appendages detaches themselves from the mutant's corpse as a Giant Spider (even larger than the mook-variety spider monsters) to continue attacking with a new life meter.
- The giant brain with an eye in the lab needs to be killed thrice, its first defeat having it collapsing, with its eyes and limbs shrinking back into its body. But alas, it instantly regenerates a second eye and replaces its limbs with tentacle barbs, and its life meter refills. Kill it a second time and its organs shrink back... before regrows yet another eye, a mouth, and four tentacle barbs. With the ability to fire energy bolts. Thankfully after the third defeat the monster then shrinks into the pool and dissolves away.
- The mutant core Final Boss. Firstly as a hovering Faceless Eye, then assuming a second humanoid shape that is pure Bishōnen Line, and finally dissolving away into a third form resembling a floating, pulsating giant heart.
- Spread Shot:
- A power-up granted to all three of the heroes. For Mituki, her spread used as a Limit Break can cover an area in projectiles.
- The giant flying mutant boss can breath an arc of five projectiles at a time to attack.
- Teleporting Keycard Squad: Inverted in multiple areas. The only exit is an electronically locked door, which you need to obtain a keycard to open, but said keycard will not appear until you've killed every single onscreen enemy the game throws at you. Once every mutant monstrosity is destroyed, a keycard suddenly pops out from nowhere for you to collect.
- Two Guys and a Girl: The three playable heroes, Rick and Vogt being the guys and Mituki as the girl.
- Unique Enemy: Some green-skinned, amphibian-looking mutant humanoid creatures appears in two areas, outside the lab and near the chemical pool, dropping from the ceiling to attack, but they do not appear anywhere else for the rest of the game. In contrast, the same area also introduces the Living Gasbag mutant spore enemies, who appears in several subsequent areas outside the pool.
- Wetware CPU: The mutant strain aren't limited to infecting organic life-forms; there are mechanical enemies, including turrets and Chicken Walkers, with visible fleshy lumps growing off their tops and sides, having been controlled by the mutants.
- Zerg Rush: The smaller insect mutants uses this tactic to overwhelm intruders. The first area in fact ends with an unfortunate redshirt getting swarmed and devoured by a horde of bugs from out of nowhere.
