Inspired by Valve's breakthrough FPS Half-Lifeand its sequel, Codename: Gordon is a sidescrolling action shooter run in Flash and designed by Paul Kamma (aka X-Tender in the Flash community) and Soenke Seidel (aka Warbeast.) the 2D platformer features elements of action games such as Metal Slug but also features event-based gameplay based on the Half-Life universe, and includes many of the creatures and weapons (including the crowbar) from the series that inspired it.