On the install instructions you guys said that to play online, you shouldn't delete the META-INF folder. However, if I don't delete it, the game won't open. But yet, with the META-INF folder deleted, it's possible to play on Lan Servers with the mod. I have played with a friend for hours, and it's working without problems.
The only thing I think that needs to be reduced is the mob spawns. It's almost impossible to leave your house without finding a giant.