The multiplayer mod looks really cool, but there would have to be massive changes to the game. Most notably, you'd have to double all the items in the game since there would be tow people in the game. Also, you're going to have to see to

. After hhe takes you to his dimension, I think he disappears. If the player gets out and tries to recontain 106 while he's trying to kill player 2, well I don't even know. Plus,

needs to pursue both players.
By the way, what happens when one player dies? I hink they should spawn in 173's chamber.
Last though, both players need to spawn together. Make a duplicate of the D-class spawn room and a duplicate of the guard. Then, both players can start at the same point.