i reached level 20 then the enemies were in the middle of the field then my dad told me to get CORNEDBEEF and then when i came back the enemies passed our base i had all the upgrades so that was the worst thing EVER that happened :( here is a tip: you can get more coins by making the level longer by 1st wait for an attack by the enemy 2nd let them kill your men 3rd then when they are dead you kill the enemy 4th repeat the steps 1-3 it works the best when you are playing in a high level i rate this game 5/5 HAVE FUN PLAYING!