I wanted to make it hard. I want it to be a "who can survived the longest type game" so i spent quite a bit of time trying to make it difficult but not impossible! You're right, buying the best gun right off the bat isnt a winning strategy, and neither is spamming the weakest gun as they will just get taken over once the harder zombies start coming! If you use the retreat and attack buttons properly you can give your army a slight jump on the attacking zombies! I would recommend a different strategy to last more than 2 min! thanks for playing!