gau-17 has an interesting feature (bug?). in defense mode, start firing with mouse pressed, then pull the gun out of the firing zone, then pull back again...no spin-up needed for subsequent shots.
makes defense mode easier.
okay so bosses are back but for crying out loudly, they are extremely hard. I had 12 3-star missile towers (well placed ones) and they only hardly killed 1 out of the 6 bosses...with all 25 lives left I was hoping for 100% completion, but then I was like hey wtf...
 "City Siege 2"){kind=icon}
 "Zilch Mobile"){kind=icon}
 "Apokalyx"){kind=icon}
 "Dino Strike"){kind=icon}
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 "The Gun Game 2"){kind=icon}
 "Great Game 1/5"){kind=icon}
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 "Scape Adventures"){kind=icon}
 "Hippolyta"){kind=icon}
 "4 Differences"){kind=icon}
 "The Next Floor"){kind=icon}
 "Little Wheel"){kind=icon}
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 "Super Karoshi"){kind=icon}