Here's a tip to get the last achievement. when you have fully upgraded, everything, fly upwards as far as possible, but keep about 1 bar of fuel for steering, let the plane stall, then instead of pressing space to bring it back, you can just press any keys, to do it even faster, than just use the last bar of fuel to steer the plane and keep it above 50m altitude until u get over 100 stars =) hope this helps.
 "Flight"){kind=icon}
 "ShellShock Live"){kind=icon}
 "Endless Migration"){kind=icon}
 "Ashes 2 Ashes: Zombie Cricket!"){kind=icon}
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 "When Penguins Attack -TD"){kind=icon}
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 "Mytheria"){kind=icon}
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 "Straw Hat Samurai"){kind=icon}
 "Escape from really boring island 3"){kind=icon}
 "Ether War"){kind=icon}
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 "Age of War"){kind=icon}