Entropy is a large and challenging Boom compatible (cl9) slaughter map with a gold and orange theme. There are two main routes to take from the start, one for plasma and the other for rockets, both must be completed in order to finish the map, so your decision wont leave you without one weapon. There are 3 new keycards that replace the skull keys, each of which will require you to beat a difficult encounter to get. Once you have all 3 you can get the BFG and will be rewarded with something...else. The map has been completed without BFG and without secrets to ensure it is balanced. Many of the fights will require some puzzling out before you can complete them. Sometimes this means simply pushing a switch when you otherwise wouldn't and other times it can mean something else entirely. This is a long and difficult map, but the other difficulties have been balanced in the hopes that people will use them. I would highly recommend that people play this map in a GL port like GLBoom or GZDoom as there are a few spots where software struggles FPS-wise. The map is still playable in Prboom-Plus but can get jittery in some of the more open areas.