The main difference between this game and Vertix.io is that whereas Vertix was 2D with a 3/4 View, Karnage is fully 3D, though it still plays similarly. Another major change is the removal of infinite reloads in favour of ammo crates. Armor system was introduced as well, and the armor kits are often placed on the small islands cut off by lava, so getting to them requires jumping - another addition. There's also a greater emphasis on the explosives, as nearly every class carries a grenade launcher as a secondary weapon, and Mr Ops class has its weaker version as a primary. Lastly, you can pick one out of five passive abilities on your loadout screen, and change them before every respawn.
In all, it plays a lot like a top-down version of Quake. In spite of the additions listed above, it is also more stripped-down than Vertix in several ways, as it currently has 6 classes instead of 10, and only 3 game modes next to the much wider variety in Vertix. Weapon camos are also its only cosmetics right now, with no sprays, hats or shirts like in Vertix. This is because Sidney soon realised that if he already made a 3D game, then he could outright create a First-Person Shooter. Thus, Krunker.io was born, and became far more successful than either Vertix or Karnage.
Tropes present in Karnage.io:
- Armor-Piercing Attack: Hunters automatically ignore any and all armor their opponent may have collected, regardless of whether they are using their rifles or pistols.
- Convection Schmonvection: Every level is surrounded by lava pools, and falling into it is instant death. Yet, standing right next to something this hot doesn't cause any harm or discomfort at all.
- Critical Hit: Every weapon has a fixed critical rate. There's also an equippable passive ability that raises it.
- Everything Fades: Dead players disappear immediately. Explosion marks take a few seconds. Bullet marks on the walls stay for about 10 seconds or so.
- Glass Cannon: The Hunter only has 60 HP, when the other classes have 100 HP, Mr Spray N Pray 200. This compensates for his ability to kill 100-HP classes with a single shot, and leave the others severely wounded.
- Hand Cannon: Franklin's revolver. It kills a Hunter in a single shot, and every class besides Spray N Pray in 2.
- Mad Bomber: Mr Ops, who is a successor to Vertix's Nademan class, whose and uses the same "Nade Launcher", which is essentially a semi-automatic grenade launcher with larger ammo capacity, but somewhat weaker grenades. He also has a damage resistance to all explosives, whereas Nademan had an outright immunity, but only to his own projectiles.
- Mighty Glacier: Spray N Pray class has the largest health and the greatest ammo capacity, but it is also slow, and deals the lowest damage per bullet. Its users can prefire really early thanks to its 200 bullet capacity, and not worry much about the rest if there's an ammo pack nearby. Even if they don't catch their enemies by surprise, they have good chances due to their 200 health. Some players outright prefer to run from any Spray N Pray players and focus on everyone else because of it.
- More Dakka: Spray N Pray has a whole 200 bullets, and only needs a fraction of those to kill someone.
- Every class can also emphasize this through the Rapid Fire passive ability.
- Non-Fatal Explosions: Unless you are wounded (or a Hunter), the explosions from rockets and grenades will not instantly kill you if you are on the outer edge of their blast radius. Oil Barrel explosions are only immediately lethal to Hunters. Rocketeers, Ducks and Spray N Pray classes can survive being at the epicenter of any in-game explosion.
- No Plot? No Problem!: As is a a tradition for both Sidney's games in particular, and the .io Game genre in general.
- One-Hit Kill: A direct hit from a Grenade Launcher kills every class besides Mr Ops and Spray N Pray. A single shot from the Hunter's Sniper Rifle does this to every class besides those two.
- However, Hunter himself is insta-killed not just by the above, but also by a single shot from the Detective's Deagle, or by a Nade (which are otherwise weaker than the normal grenades.)
- One-Hit Polykill: Hunter's sniper rifle can kill two or more players at once.
- Regenerating Health: Available as a passive ability. Otherwise, you need to rely on the medkits.
- Short-Range Shotgun: Averted; shotgun's range doesn't appear meaningfully shorter than that of the other classes, as it easily travels far beyond your sight range, (which to be fair is low, since every level is a pretty narrow maze).
- Sniper Rifle: Used by the Hunter class, and does 100 damage per shot. It also has a whole 15 bullets, to compensate for the inability reload indefinitely often, like in Vertix.io (and eventually, in Krunker.io)
- Spread Shot: Vince's shotgun fires a spread of 3 pellets.
- We Will Spend Credits in the Future: The currency earned at the end of the rounds is kredit, shortened to KR.