What do you think of the multiplayer mode?

I've played a few runs and I think it lags. My wifi connection is good, though. What I find a shame with this mode is that there's only 1 item in the treasure rooms, whereas there are 4 items for the bosses. In order to improve this mode, players would have to be able to split up. When you take an item from the treasure rooms, you can't take the next one, just like when you have a choice between 2 items. And to move on to the next floor, all players would have to be in the boss room.