Animation

Mega Man 2.5D originally started as an animation using 3D modeling software designed by Peter Sjöstrand in 2009, which eventually was posted to YouTube as a proof-of-concept.^[3][4] He was inspired to make the concept while shopping at a mall and, while there, waiting for his friend to finish shopping by using Legos to make characters from the Mario and Mega Man series. This led to him using Autodesk Maya to create 3D models using cubes, creating a sprite of Mega Man. He eventually made more objects, and eventually created the animation.^[5]

Video game

Once the video was uploaded, the video's popularity lead Sjöstrand to begin talking to some programmers to discuss turning it into a video game.^[3][4] For a large portion of the game's development, the work was done by Sjöstrand and lead programmer Edgar Cebolledo. Later, two more people joined the protect, Johan Sjöstrand and Ontikarus Ryan, who assisted in multiple areas, including game testing and programming.^[3] Before release, the game was designed by no more than six people.^[2]

When designing the levels, the team has a rough sketch of the level made and expands upon it from there. As they do more work on the stage, they sometimes had to go back and tweak things once they saw them in action.^[3] For Sjöstrand, one of the most difficult parts of developing Mega Man 2.5D was making sure it felt authentically like a Mega Man game in terms of physics.^[3] When looking for inspiration, Sjöstrand played through the Game Boy Mega Man games, while Cebolledo watched streams of NES games and played newer games.^[3] One series that they took inspiration from when designing a level was the Mario series.^[3]

When working on the co-op mode, it was planned that levels could be played in either single-player or cooperatively. However, Sjöstrand found that the changing camera only worked in single-player, and content designed with co-op play in mind could be impossible alone. Sjöstrand did not want to compromise by making levels that work in both modes, and thus decided to have separate stages for single-player and co-op.^[3] The team made a point of trying to include co-op mechanics that would both be simple and fitting in a classic Mega Man game.^[3]

Robot Masters from various Mega Man games were included in Mega Man 2.5D, and the designers chose which Robot Master to include based on whether they felt they could expand upon their stage. They offered Snake Man from Mega Man 3 as an example, where they added enemies from Battletoads.^[3] They also Splash Woman from Mega Man 9, where they added water elements from Mega Man 2 and Mega Man 5.^[3] They chose to include Splash Woman because they felt it was a more interesting choice than Bubble Man from Mega Man 2, but kept level elements from Mega Man 2 and Mega Man 5 in order to make Splash Woman's level more varied.^[3][6] Quick Man from Mega Man 2 was added based on his recognition, as well as his weapon and stage.^[3] Quick Man was particularly difficult to implement properly, as when they sought information about his movement patterns, they found that he has so many as to be seemingly random. Instead, they had to play Mega Man 2 in order to get a feel for his patterns.^[3]

Mega Man 2.5D was composed by Magnus Palsson, and the soundtrack was composed with the intention of evoking Mega Man 2 and Mega Man 3. When composing the music, Palsson made a point of trying to mimic the series' music in terms of conveyance of emotion and story. He stated that he wanted to evoke the familiar Mega Man music while also doing something new. Some songs on the soundtrack are covers, while others are "something that sounds like [Palsson]."^[7]