buy boost to 500% or 600% to all then fight arena ( very good for exp) or play pong ( red enemey is the easiest yellow is also easy) this will give very much exp and gold.
the rankings are full with hackers cant understand that noone is doing something against them there are the same people leading the highscore for several days with an score which is impossible. poor kongregate :-(
for all who have problems to finish the later levels: Go back to the beginning and do all lowlvls on each possible mode. You will get so much exp that you can beat the harder lvl.
For example since now i have only finished 2 arcane guardian levels, but i am lvl 54 ^^
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 "Back2Back"){kind=icon}
 "Paradox Embrace"){kind=icon}
 "How Evil Are You?"){kind=icon}
 "Take Something Literally"){kind=icon}
 "The Tickler"){kind=icon}
 "Frantic 2"){kind=icon}
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 "Battalion: Arena"){kind=icon}
 "Paladin: The Game"){kind=icon}
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 "GemCraft chapter 0"){kind=icon}
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