Art is good and good choice on the music!
Took me a while to realize I can't drag and drop heroes to the quests but have to right click first then left click to assign (is that not intended?).
I think you don't really have to add timers in this game at all, or at least no like testing my reading speed and reflexes. With more information provided/discoverable to the player, the player can make more informed choices and this will become a good strategy/management game. In any case, there is great potential in the idea.