A perfect game means your castle has full HP at the end of the round. I think but i'm not sure, all monsters have to be dead before it says you win.
Leech can help you get it, but if you use a repair kit you won't get perfect. ._.
that focus feature is bullshit. i needed 1 more rifle level to get to use my new gun, but no i get bullshit choices for 3 levels, which the next leveled killed me on hardcore mode.
Lol glitch: I used ragnorak and the dragons raped my castle, but i never got game over. My caslte's hp is at negative forever and keeps going down each round ;)