Nitrometris is one of seven games in Mega Mash, as well as part of the Minigame tool in Rubble Trouble Tokyo and Rubble Trouble Moscow. Nitrometris is the smallest of all the seven games in Mega Mash, each zone being the same, only different sizes. Nitrometris stars characters also called Nitrometris, who appear as blocks made of many coloured Cuboy faces.
Nitrometris is set in a bluish-grey world in Mega Mash. Nitrometris fall from the top of the ceiling, and stop falling when they come to the bottom. If there is no stable platform beneath them, the player will fall out of the zone.
Nitrometris plays like a usual game of Tetris - blocks will fall from the top of the zone, the player being able to rotate them. Once a Nitrometris block touches the ground (or another Nitrometris block), it will become stable in a few seconds, and unable to be moved. If Nitrometris make a tower to the top of Zone, that when another Nitrometris block comes down that part of it will stick out of the zone, if this happens, the zone will fill up with tan blocks and the player will lose a heart, restarting the zone with no Nitrometris in it. If there is no solid ground below a Nitrometris zone in Mega Mash, when the player reaches the bottom of it, they will fall out of the zone.
- Main Article: Tetris blocks
Tetris blocks are blocks made up of coloured Cuboy faces.
Nitrometris was first seen in the NES skin. This image of Nitrometris looked very different than Nitrometris in Mega Mash. In the image, there are two sections of the screen, one for player 1, the other for player 2. As seen in the image, one of the seven letters that make up the word "Nitrome" would fall from the top of the screen, in the font Nitrome uses for their logo.
Each letter was made up of many coloured Cuboy heads. A middle screen showed what seems to be the remaining letters left to fall. Cuboy was placed in the bottom middle of the screen, and the game seemed to have a score. This image was meant to be a parody of the Puyo Puyo series of tile matching games (similar to Tetris).
One of the seven images Nitrome previewed to fans when announcing Mega Mash was a Nitrometris one. This image had several shapes usually seen in Tetris falling from the screen, made of Cuboy heads.
- Nitrometris is the word "Nitrome" with "tris" added to end, tris being part of the word tetris.
- Nitrometris is the smallest of all the games in Mega Mash, having no enemies, interactive objects, or hazards.