I realized there's level 4 doesn't work, maybe you could fix it :)

If your too lazy to do anything for all upgrade badge,i advice you to use some units and play epic for big bang. Put the units bout 3/5 distance of horizontal map and use the auto arrow power,so the thing is when the bomb comes, your army attack with the help of auto arrow,so you can just stay afk and grind for gold because when your army 'kills' the bomb. they also die and reborn and this continues the cycle.