[Devil Daggers]'s art direction and rendering engine were designed to reimagine the aesthetics and graphical style of video games from the 1990s. This was achieved by making use of unfiltered textures, jagged 3D models, and the deliberate implementation of polygon jitter and texture warping found in early 3D games.
https://www.reddit.com/r/Unity3D/comments/49385e/how_was_the_graphical_style_of_devil_daggers/
https://www.reddit.com/r/gamedev/comments/4zwz40/how_did_sorath_do_the_art_assets_for_devil_daggers/