The run-and-gun platform genre was popularised by Konami's Contra.[10] Gunstar Heroes and Metal Slug are also among the top three popular examples of this style.[11] Side-scrolling run-and-gun games are an attempt to marry platform games with shoot 'em ups, characterized by a minimal focus on precise platform jumping and a major emphasis on multi-directional shooting. These games are sometimes called platform shooters. This genre has strong arcade roots, and as such, these games are generally known for being very difficult, and having very linear, one-way game progression.