There is a popular niche for building 3D models of the tanks and characters from the game using paper.
Depending on what you're looking for, "paper" for Metal Slug X usually refers to one of two things: physical collectibles or DIY papercraft models. metal-slug-x
If you want official or reproduction artwork on high-quality paper, there are several options for game room decor: There is a popular niche for building 3D