(Disclosure: This site contains product affiliate links. We may receive a commission if you make a purchase after clicking on one of these links. Read our affiliate disclosure for more info.)
The developer of Spelunky YellowAfterlife has released a new multiplayer mod called Spelunky SD for the free game Spelunky Classic.
Spelunky SD is an expansion and modification Spelunky Classic.
It includes a number of fixes and tweaks to the game, and, most notably, adds a cooperative online 2-player game mode.