Set up a nice perimeter of defense stars, and send ships to them, let it build then attack with those ships, that way the satellites are attacked at one time and completely destroyed.
You level up by getting accomplishments! "Accomplishments?? WHAT?" Click on your name in chat, if you beat any boss in your recent activity it will say you got that accomplishment, click it, and you see a list.
Sparta mode:Buy a grenade launcher, max it out, buy 3 missile launchers, max out their AMMO and one cant be maxed out, upgrade its firerate instead, im not sure if you have any extra cash to buy gunmen or repairmen.
 "Battalion: Nemesis"){kind=icon}
 "B29 Assault"){kind=icon}
 "StarBaron"){kind=icon}
 "Zombies!"){kind=icon}
 "Drunken Masters"){kind=icon}
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 "Anaksha: Female Assassin"){kind=icon}
 "Sprout"){kind=icon}
 "The Last Stand 2"){kind=icon}
 ":the game:"){kind=icon}
 "Seven Deadly Sins"){kind=icon}
 "Dark Cut 3"){kind=icon}
 "Kongregate Forums"){kind=icon}
 "Storm the House 3"){kind=icon}
 "The Last Stand"){kind=icon}
 "Idle 2.: Konquest"){kind=icon}
 "Idle."){kind=icon}