Before Spelunky became a big hit on Xbox Live for Xbox 360 in July 2012, it arrived on PC in late 2008 in its original state. Source code for the original game was made available one year later, and just now received a new mod called Spelunky SD courtesy of Ukrainian developer Vadim. The mod adds, among other things, online co-op multiplayer to the first version of the game.
In what started as a weekend project, the developer spent three months fine-tuning the mod for its first public release late last week. He tweaked the original game in a few ways, adding elements such as making enemies blink when they're about to get up off the ground. Vadim fixed a few bugs as well and made input precision "slightly more forgiving" in the game. The Spelunky SD mod is available to download through Game Jolt - check it out here.