The game is easy,use your money on landmines then get near enemy towers,after that use 2 landmines then strike the tower with your normal attack to destroy instantly
There is a secret gun after you get your 3rd gun then you can get another which is the fourth,The fourth takes a long time and you have to keep gaining xp it'll seem slow but later you'll see it half way,all you have to do is kill alot of those big dudes.
i found a glitch i was fighting a boss and i rapid fire and sent all my troops then she went out the game with tiny hp left i had to wait for the timer to run out