After playing level 9 a zillion times....I adjusted my thinking...Upgrade bombs to the max...then upgrade electric tower to the max..then upgrade slow traps....these are the best three weapons..build electric towers on level 9 and some slow traps as they become affordable..always leave yourself some money in reserve to bomb the heck out of stuff that doesn't die...I only use these three weapons....and an occasional cannon and machine gun just cheap ones though.. do not waste money on the towers that don't help...bombs are the best weapon without a doubt.....I have since 3 stared every level....
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