From Wikipedia: N+ is the console and handheld version of the game originally made for systems powering Adobe Flash, N, which was developed by Metanet Software. N+ for Xbox Live Arcade was developed by Slick Entertainment and published by Metanet Software. Unique versions of the game were also ported separately to the PlayStation Portable[1] and Nintendo DS[2] by developers SilverBirch Studios and Atari.[3] Metanet Software licensed their N IP for this deal, provided single player level design for both versions, and consulted on the project.