- Awesome Music: Tons. See here.
- Demonic Spiders:
- The Mimic Green Enzymes from Test Subject Green were designed in-universe to be this. Capable of copying the powers of most of the Oranges, they'll approach Blue and start mimicking his every move, instantly killing him if it gets too close. Not only will you then have a murderous enzyme chasing you and copying your movements, they're annoyingly difficult to deal with too, since they're mobile and can mimic Shield enzymes to block a hit if shot when on the ground - and in case you thought killing it before it detects you is an option, its passive state is too low to hit even while crouching, and exploiting terrain to hit it will just have it mimic Dodge to avoid the hit. The worst part is that you cannot fight them, period, as unlike every other enemy in the game, they'll respawn instantly if killed.
- Employees/Workers in Nitrome Must Die have large amounts of health, are surprisingly mobile, and can wield any of the weapon types in the game depending on what map they're on. While they're always more threatening than most other enemy types that appear on their levels, their difficulty can go from hard to hair-pulling if they happen to have a very strong weapon on hand, particularly Rockets (see below). The suited variants of the employees not only have more health, but they have a whip attack they can use to extend their melee range, and sometimes are carried by Employees to more than double their HP and firepower.
- Even Better Sequel: Skywire 2 and Test Subject Green are the most notable, but almost all of the sequels are on par with the original in terms of quality.
- Growing the Beard: Everyone agrees that it happened, although it's hard to identify a specific point. The most common place to put it is the release of "Skywire 2".
- Scrappy Mechanic: In Swindler 2, the titular character gains the ability to detach from his rope and roll around the level. Not only is it hard to control, but you have to constantly regain air because he apparently can't breathe without it. It does nothing to enhance the game.
- That One Attack:
- In Nitrome Must Die, the Rocket is this in the hands of an enemy, considering that its projectile is fast as hell, deals splash damage, and takes out anywhere from a third to half of your health in a single hit. Since Employee enemies don't have its regular limitation of low ammo, there's nothing stopping them from just spamming the hell out of this, potentially spelling an instant death if you're not careful. Fittingly, the Final Boss uses this weapon for one of his phases, and it's telling that the fight actually gets easier when he switches to the much less damaging Homing Rocket. Its saving grace is that the same weapon is a One-Hit Kill on almost all enemies if you happen to have it.
- From the same game, the Molotov. While it's arguably easier to avoid than the Rocket, the resulting fire waves travel along the full length of whatever it landed on, deal ridiculous damage, and ignore invincibility frames while still putting players into hitstun, meaning a single enemy Molotov can easily juggle and instantly kill a player. While players can also use this to gib even the toughest of foes, it can deal self damage, so a player can potentially stunlock and kill themselves with an ill-placed shot, making it this in the player's hands as well.
- In Mutiny, just about any ability with global range can be this. The Tidal Wave in particular stands out, as unlike the others, it's not limited by terrain, doesn't need to be aimed, and will hit everything in the lower half of the map for massive damage. Some maps start your whole team on the bottom half, only for an enemy to whip out a Tidal Wave on their first turn.
- From Steamlands, some weapons are exceptionally dangerous in the hands of an enemy.
- The North Star is a minigun that deals an absolutely ludicrous amount of DPS and can instantly shred most defenses before doing the same with the rest of your tank. You might be tempted to try and loot it for yourself upon seeing an enemy with one, but due to it being both a large and high priority target, chances are the only way you'll even end up surviving the encounter is to outright take out the North Star.
- Thor's Hammer, a railgun that fires hitscan blasts that cannot be avoided and inflict massive amounts of damage per shot, making it liable to instantly take out key defenses or tank components. Worse still, a full-health Thor's Hammer has deadly precision, so it's not going to miss - and not even Reflectium will save you since it's the only gun in the game that outright ignores it.
- Zeus, which borders on Purposely Overpowered. Being the final upgrade to the Matryoshka and Mandelbrot mortars, it shares its Recursive Ammo cluster bombs, but amps their damage up to ridiculous levels to the point where one direct hit can blow gaping holes in reinforced tanks and One-Hit Kill most turrets. It's also one of the guns that can partially ignore Reflectium Armor, which can potentially make the damage even worse since each reflection will cause its bombs to release an additional explosion, dealing more damage. While it's a huge target, it has the appropriate amount of HP to match, making it hard to destroy or steal without entering a prolonged fight with its user. Its saving grace is that it's one of the rarest guns in the game, with the levels it appears in ranging in the single digits for each of the games.
- That One Boss: Boss 12 from Sky Serpents is probably considered the most awkward/difficult due to its fireballs and needing to memorize the layout and timing all of the jumps perfectly. Fittingly, it was chosen to represent the game as a boss in Nitrome Must Die out of all the serpents, although it's significantly easier there.
- That One Level:
- Cave Chaos 2 has its minecart level. The gist of it is that you need to ride a minecart across rails. Sounds simple, right? Well, the rails' collision detection is set up in a way that the minecart sits on top of them fine, but you go right through them. Even worse, bats place down the rails progressively, and this combined with the game's wonky physics means you will be falling out of the minecart to your death. A lot.
- Level 12 of Mutiny, where your pirates are outnumbered 5 to 11, and the skeletons aren't weak either, exacerbating your numbers disadvantages. To make things worse, the level is broken up into a series of tightly-spaced islands, making it difficult to navigate and aim your weapons properly while letting the skeletons isolate your units before ganging up on them. God help you if the CPU decides to use a banana...
YMMV / Nitrome