A teaser screenshot of the game as seen the NES skin
Surface is a cancelled Nitrome platformer game. First teased in the NES skin, Nitrome later released a video on March 24 2011 explaining and showing the game's main mechanic. No information was disclosed about the game until June 2012 when the game was mentioned as having been cancelled.
Surface is a platformer, however, although being a platformer, the game would feature a unique mechanic where each level of the game would take place on a 3D shape, the player controlling a 2D character who would be able to walk on each of the faces of this shape, each face having a 2D setup with 2D platforms and other 2D objects.
From what has been seen, the only 3D part of the game would be the 3D shape which all 2D parts of the level are arranged on to. Each 2D face would act as any regular platformer, the 3D shape only weaving each 2D part of the level together. If the player goes between edges of each face, their sprite will be present partly on both these faces. As seen in the tech demo video, if the player is falling and impacts a vertex of a side of the square and there is a wall below them that they cannot stand on and a wall adjacent to them, the player will be flipped ninety degrees. 
The shape would automatically rotate whenever the player walked from one face to the other, although the player could also manually rotate the shape, according to the tech demo video.
From what has been seen from the tech demo, the game would likely only use shapes with square faces. Although no content for the game has been revealed - with the exception of the concept of platforms, moving, and jumping -, the Nitrome 2.0 skin revealed that the game would feature a small oval shaped object, an object that resembles the shape and placement of objects in other Nitrome games that could be collected for points.
A tech demo demonstrating Surface's gameplay mechanic was created by Nitrome early on in the game's development and was also shown in a video titled "Nitrome - 3D Game Tech Demo" that Nitrome uploaded to their Youtube account on March 24 2011. This video was narrated by Mat Annal and Luis Romero and covered early development of Surface and later on used the tech demo to shown and explain the game's gameplay.
In this video two levels of the tech demo were seen, the first level being a 3D cube and the second a 3D L shape. Both levels had a transparent screen at the top left of the game that showed the coordinates of the player and parts of the cube.
Purely for the purpose of illustrating what the main gameplay of the game would be, Nitrome used assets from the Twin Shot series to test the game, the orange angel serving as the playable character and the blue blocks serving as platforms. The use of Twin Shot assets was purely for testing the game and did not mean it would be in any way connected to the Twin Shot series.
As a tongue-in-cheek joke since the tech demo was also being developed around the time the NES skin was being created, a graphically downgraded version of the game in wire-frame graphics was put into the skin.
Surface's gameplay mechanic was inspired by a video of World 1-1 of the Nintendo Entertainment System Super Mario Bros. being played while projected on to a wall, this projection also known as "augmented reality". Nitrome saw this video in early 2010 and were intrigued by the projection and the idea of playing a 2D game on a 3D surface, and from then on the idea was frequently discussed among staff and toyed with.
Development of the game had started prior to January 24 2011, as it was on this day Nitrome released the NES skin which included a cameo of Surface. When development started Nitrome wanted to spend a lot of time working on the game in order to perfect the game's main mechanic. When work on the game started a tech demo was created to test out the game's mechanic, the first level created being a cube.
One of the planned additions to the game's concept were different shaped levels, an L shape used as an example in the later-revealed tech demo. The game's programmer was Luis Romero who created the 3D engine for the game. The cameo of Surface in the NES skin attracted a lot of attention and was met with a lot of praise from Nitromians, resulting in many emails to Nitrome asking for them to make a game using this mechanic.
On March 24 2011 Nitrome upload to their Youtube account a video of the created tech demo that also included an explanation about the game's mechanic, uploaded because they were seeing other developers creating games with a mechanic similar to Surface's. Nitrome planned to share more information about the game in the future, although this never came about. The game was still being worked on around the time the Nitrome 2.0 skin was being created, a skin released on August 25 2011 and containing a cameo of the game.
Despite the enthusiasm for the game, it had been cancelled by June 7 2012 for multiple reasons. The project being very large and the time required for development making it not feasible for a free browser game was the main reason for it being cancelled; the game's continued development severely slowing down work on other browser games was another contributing factor. Furthermore, because other companies released or were developing games with a similar concept, the game's mechanic seemed less original.
Despite the game's cancellation Nitrome is still very interested in revisiting the game as they still see it as having a lot of potential. In August 2015, Nitrome said that they were open to trying out Surface's game concept in Unity (the engine used to make all of their current games), but were unsure if it would work in that engine.
Surface was first hinted as a tongue-in-cheek joke in the NES skin, appearing drawn in wire frame graphics. The content in this image was of general content found across many games, such as an entrance and exit door, platforms, and spikes.
Although relatively obscure, what is possibly the main character of the game can be seen on a building of Balloons Inc. in the Nitrome 2.0 skin, on the building below the one Hot Air is on, the building with a large cloud.
This design - the small character on a platform - is shown to be from Surface as part of the person's platform extends off that side of the building, on to the building's visible wall. Featured on the platform the small character is on are small oval objects, possibly collectible objects.
- The arcade game Battlezone displayed a wireframe view and had the same background as the NES skin cameo Surface image.