Startups are short animations played before the game loads the main menu. Every startup is also accompanied by the Nitrome jingle, playing after the animation occurs.
After a pile of leaves move, the squirrels are shown by a wood carve-out of the word Nitrome while the red squirrel holds a chainsaw and a protective mask.
A fly flies toward a pink flat shape, when the fly gets close the pink flat object snaps shut to form the word Nitrome (as a reference to the venus fly trap).
The pink letters of N, I, T and R bounce over the green letters of O, M and E, mimicking the movements of the angry heads without the chain. The two letters come together at the middle of the screen.
The letters "itrom" fall between the "N" and the "E" and complete the electrical current, causing sparks to go between the letters and light up the word Nitrome.
The spartan attacks a statue of a mermaid that reveals the word Nitrome. After the spartan leaves, an artist comes, says "Oh! My statue!" and cries over his lost work.
The bats place three green gems, and then a red gem a little bit farther and a little bit higher then the green one. Then, the bats place four rock platforms underneath the green crystals, and the brown miner jumps onto the purple rock and runs to collect the three green gems while the rock platforms fall off-screen, revealing the word Nitrome.
The wizard uses a spell and makes all the Nitrome letters grow up, only until one letter does not grow up. The wizard struggles trying to make it turn up, turning red twice. The letter then grows up.
The Nitrome letters are all floating in the air. The "N" and "E" of the Nitrome logo move over to each other, then turn around and shoot down all the other letters. The N and the E turn to face each other, with the N shooting the E and the E shooting the N, falling into place.
The letters N-I-T-R in green with frog's eyes, and the letters O-M-E in pink with bunny ears jump around before jumping into position, making the Nitrome logo. Every letter looks like a head on Ribbit.
The game cartridge for Super Treadmill is put into the Nitrome Enjoyment System. The "P" button is pressed several times. The cartridge is taken out, blowed on (only heard as a sound), and put back into the system. The P button is pressed on again, this time successful. The message shown when a game cartridge is put into the original Nitrome Enjoyment System is shown, with directions at the bottom saying to ignore it.
The Silly Sausage cartridge is about to be placed into the Nitrome Enjoyment System, but the Game Muscle cartridge is suddenly attached to the Silly Sausage cartridge. It is inserted into the Nitrome Enjoyment System and the "P" button is pressed. Notably, the Nitrome logo is placed on the top of the screen instead of the middle.
The game cartridge is inserted into the NES and the "P" button is pressed. The Nitrome jingle is heard, but abruptly loses pitch. Afterwards, the display of games in Mega Mash is seen, but there is a fizz on the screen, giving the impression of a "glitchy" game.
Next, the game cartridge is removed, and smacking noises are heard once it is out of the screen. It is then inserted back in the NES and "P" is pressed once more. The full Nitrome jingle is heard this time, with smoke trailing out of the game system.
Letters forming "The 100th Nitrome Game" are flying from the upper left corner. The background is pink with the Cuboy faces. The player hears a drum-roll, and suddenly a typical "Alarm-sound". The background is blinking red, and turns black/grey, Cuboy turning into a skull. Pistols shots come flying off screen, into the 'T' and 'E' of 'The' and the 'T' of '100th' disappears, along with the 'E' of 'Game', with the 'T' of 'Nitrome' moving a bit back. There are some bullet wounds in the letters. Then, some B.C. Bow Contest arrows fly into 'The 100th Nitrome Game'. Big rockets shoot in 'The 100th' and 'game', and explode, hitting the word 'Nitrome'. Little pieces of Nitrome are burning down. After that the typical Nitrome jingle is heard.
Similar to the first Cave Chaos, bats arrange a short platform of blue rocks that the brown miner crosses while collecting the gems above the platform. The game's background design and refined artwork are seen during this startup, however.
Against a checkered light-blue background, Hot Air's driver jumps on a pump to inflate the letters "Nitrome". This is similar to the startups of the previous Hot Air games.
The letters "Nitrome" descend from the top of the screen in black against a rainy background. The black then drops off, revealing the letters in orange.
Several blocks, including a turret, move along a coloured line, which is followed by the Nitrome logo. When it reaches the peak, "N" stays there snoring, while "itrome" slides back down to the center. Then, "i" maneuvers under the "N" and shoots it, waking it up and completing the Nitrome logo.
The letters of "Nitrome", aside from the "r", move in a jerky motion towards the centre of the screen, either from the top or bottom. The letter "r" then starts to move towards the "t" position, but shifts to the right to fit in the missing hole.
Similar to Swindler's startup, the letters of "Nitrome" descend from sticky green cords. This time, however, the background is orange instead of purple.
Doctor Nastidious tries to grab the letters of the word "NITROME" with his hand, "I" shoots the doctor's hand and the other letters ("NTROME") call "I" and "I" jumps back to form the word "NITROME".
Outlined letters appear against a white background before bursting into different colours rapidly. The end result is the letters "nitrome" in grey, against a white background.
Green with the letter I shoots Blue with the letter N, followed by a mercenary with the letter T shooting Green, followed by the Rex209Professor with the letter R, followed by Orange with the letter O attacking the Professor, Orange getting attacked by Rex209Blue with the letter M, followed by Doctor Nastidious with the letter E shooting Rex209Blue. He then does his evil laugh, when the Professor comes and attacks him, and starts to do his victory dance.
The Nitrome letters are glitched at the start and are in a green field. After a few seconds the screen starts glitching too and all the Nitrome letters are completely revealed.
Several bumper cars fly across the letters "Ni", "t", "ro" and "me", forming the word Nitrome. Two robots drive past the word, with their trail replaced with a black and white checkered flag design.
Several vampire bats are seen hanging from the word "Nitrome", when suddenly several wooden stakes are fired from both side of the screen, killing the bats. One bat is left, which flies up above the word "Nitrome", only to be killed by a stake which is shot at it.
Many bubbles float upwards and an anglerfish appears with the Nitrome logo outside its mouth. Notably, the Nitrome jingle is sped up, much like the one in 8bit Doves. This is the last Flash game to use the Nitrome startup.
The word "Nitrome" is drawn on a blueprint paper in white pencil. After that, a scanner goes over the word sketch and then turns it into a 3-D image of the word. The word "demo" appears in small, flickering computer letters underneath.
Cuboy appears as a jar of jam which flips its lid up, then is splattered with jam which is then moved back to reveal the word "Nitrome Jam 2014", which appears next to Cuboy as a jar.
On other games such as Computer Dreams, the logo is shown on a pink background.
A remake of the Feed Me startup, except having a green background instead of a brown background. A fly from the to-be-released sequel flies from the top of the screen in a slight wave motion and lands on the fly trap, only to become startled as the fly trap closes. The fly trap snaps shut to reveal the Nitrome logo, which then shines.
Doves are seen as bird chirping is heard, then the letters of the word "Nitrome" fall onto the screen. Everything is colored in green-grey. Notably, the Nitrome jingle is sped up.
An incomplete Nitrome logo consisting of ITR M is seen, then a robot arm comes and drops sequentially an O, E, and N.
2015[]
Starting with Silly Sausage in Meat Land, the end of each startup is accompanied by a speech bubble with Cuboy that appears at the top right side of the "e" in "Nitrome".
The letter "O" stylized like a Gunbrick rolls on to the screen and shoots upwards, causing the rest of the Nitrome letters to fall and complete the Nitrome logo.
The letter "O" with a balloon attached appears floating above the almost complete word "Nitrome", when a hand appears and draws a circle that pops the balloon causing the O letter to fall and complete the Nitrome logo.
The letters "itrome" appears normal and then the stretchy dog (near the word) stretches to form the letter "N". Cuboy appears in a speech bubble at the end, the first appearance of what would become a regular occurrence throughout later Nitrome startups.
The word "Nitrome" is thrown from off screen (accompanied with a Kiai) and hits a wall, leaving cracks in the wall. The word then moves a bit back and falls on to the floor, bouncing a bit. Small thin pieces of the wall fall off (making a glass-like sound), exposing the brick part of the wall.
The word "Nitrome" appears upside-down, then the seagulls fly by and one stops and stands on the word, pushing the word downwards and causing it to rotate in a circle then appear normal. The startup does not use Cuboy at the end.
A mimic of the Turnament startup. The letters of "Nitrome", aside from the "o", and a slime appear stationary. The letters then move in a jerky motion towards the centre of the screen and then the letter "r" enters the screen and moves into position and hits the slime, which dies and reveals the "o". Again, the startup do not use the Cuboy speech bubble at the end.
A king holding a lever while on his throne watches two yellow shelled creatures bring the letters of the word Nitrome. The first shelled creature enters with the "O", "M", and "E" letters, drops them in that order, then leaves the screen and the second shelled creature enters with the "N", "I", "T", and "R" letters, dropping them in that order and completing the word "Nitrome". The second yellow shelled creature tries to walk off the screen, but as it walks over a panel on the ground the king pulls a lever which opens the panel and causes the shelled creature to fall into it.
The word "Nitrome" is green coloured, except for the N which is a puffing wall. A mouse moves up behind the N, which puffs out, pushing the rest of the word to the right and scaring the mouse so that it runs into its hole.
The screen is split diagonally into a yellow world at the top and blue world at the bottom. The yellow word Nitrome, standing on the diagonal line in the blue world and appearing inverted, jumps up, falls down and into the yellow world, where it lands on the ground and appears purple coloured and normal.
A wall with the word "nitrome" in pixel letters is seen, then the Flat Pack protagonist is thrown into the wall, and the word pops out in 3-D and falls to the ground. Cuboy in the speech bubble appears in 2D and then suddenly pops out in 3D.
A copy of the Colourblind startup, with the only difference being the Cuboy appearing at the end of the animation, and then disappearing. The letters move down after all the animations occur too.
The letters appear as "ritNemo" at the beginning, then the "N" is moved up and the "R" is moved to where the "N" was placed, then the "N" is moved to its normal placement. After that, the "E" is moved down and the "O" is moved to where the "E" used to be, and the letter "E" is moved to its normal placement to form the word "Nitrome".
An ancient temple floor is shown, upon which a BFC (a parody of KFC) food container drops. After this, three chicken nuggets, fries, two chicken drumsticks, and coleslaw drop into the container. Blue sauce is applied horizontally across the food, as if squeezed out of a bottle. The letters of the word Nitrome then fall on to the food.
Tucker runs down a straight road in the city while several bombs fall around him. The letters of "Nitrome" fall right before Tucker runs off the screen.
When the game played in landscape mode, the startup is zoomed out further than usual.
The letters of the word "Nitrome", appearing blue coloured and some having enemies, enter the screen moving in large circles towards the middle of the screen to form the word "nitrome". The word then changes to yellow, throwing all the enemies off the words.
Bulbous dry slime covering something is shot by light-coloured orbs, which destroy the slime and reveal the word "Nitrome". Note that Cuboy in the speech bubble glitched out.
The letters of the word "Nitrome", appearing green, fall on to a floor that has two small pieces of pizza, one which is partially eaten. The letters leave green residue.
The word "Nitrome" appears, except the "o" is replaced with a flag and has a hole on the ground in front of it. The sound of a ball being hit is heard and the ball moves quickly on to the screen, bounces off the wall, and is directed into the hole. As it enters the hole, the flag turns into a "o" and the hole disappears.
The gray colored Nitrome letters bounce to reach a chili. The "E" starts smelling it, then it eats the chili in two bites. Shortly, the "E" alerts and jumps while breathing fire, which makes the whole word to turn red.
The letters of the nitrome logo are seen facing in different ways, when a weakbone runs past the faultily arranged letters, flipping them into their proper position. The jingle can be heard, and the cuboy logo appears, as usual