AlchemyWads2a.wad is a collection of selected maps which replace MAP01 to MAP18 of Doom 2.  Here are the authors of the eighteen maps:

MAP01-MAP07 - Originally ODYSSEY.WAD by Robert Chapman, titled "Odyssey"
MAP08 - Originally MAIN2D2.WAD by Guy M. Babin, a house themed map
MAP09 - Originally CCT2.WAD by Karthik Abhiram, titled "Congestion Control 2"
MAP10 - Originally CASTEVIL.WAD by Stanley Stasiak, titled "Castle of Evil"+
MAP11 - Originally ACK.WAD by Parapsyche, titled "Purged"
MAP12-MAP16 - Originally PURGATRY.WAD by Stuart E. Duff, titled "Purgatory"
MAP17 - Originally CARIBEAN.WAD by Aluqah, titled "Horror in the Caribbean Sea"
MAP18 - Originally THEMATIC.WAD by Lutrov71 and Jimi, titled "Thematic Elements"

+Converted from Doom to Doom 2.

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