a tip for the boss, wait till all five fairie flies appear, then wait till that damned snake goes of screen, capture all five then run straight to the rune.
finish a whole map, after that, you can have a new hero and new cards but still keep the first ones you gained on your first map., repeat the process, until you are satisfied with your cards,...
i dont think playing for 3 hours every two days would do any damage, but i once played for 10 hours each day for a whole month though,... hahahahhahahaha =p
didnt get my hard badge, i have to start all over again, btw, if you destroy all the gate/portal/whatever things in level 7 before reaching 200 kills, you wont be able to get out of the level, unless you quit.