A few days ago ryg released his - as he says - "very big DOOM 1 map ready for playtesting". It is a BOOM compatible map tested it with PrBoom. It uses the original Doom IWAD and is a single level on E1M1. Playing time is between three and four hours and it is intended for advanced players that know their way around an old-style map. The complete thread with all additional information can be found at the official development thread over at Doomworld.