newly released mod for the 2013 PC version of Mossmouth's roguelike platformer Spelunky enables custom seed functionality, allowing players to bypass the game's random level generator and replay specific level layouts.
The "Seedlunky HD" mod automatically generates repeatable level layouts based on any entered text string. The added utility is especially useful for competitive purposes; players can distribute seeds among friends, subjecting them to particularly challenging levels. See if you can create a series of dark stages filled with tons of instant-kill spikes. Your friends will love you for it.
Spelunky already offers a similar feature in its Daily Challenge mode, which pits all players against pre-designed level layouts as they compete for leaderboard rank. Daily Challenge levels are only playable once, however, whereas Seedlunky HD-generated levels can be loaded and replayed at will.