Almost all of the top 50 decks are virtually the same. Firefly, firefly queen, graboid, and lycanthrope. It is very hard to deal with that much efficient aggro. We need a cheaper version of rain of fire. To balance you can make it affect both players' creatures. The other common deck is poison, but purify easily deals with that.
Also, perhaps you should think about making an official website for this game. I think it would be a good idea.
It takes a double click to use slow time. Lags often. Using P as the pause button is pointless. P is so far away from the other buttons that by the time you click it you will have been hit. Seriously, I dont care if P stands for pause, it is too inconvenient to use effectively.