I've already killed a couple of spiny ships with the shots left over from the previous wave. With 30 or more lives, you get the pop-gun, this is as good as it gets, but you'll feel invincible with it, it takes out aliens very quickly. Get the spiny ships first in this wave.
Wave 62
Watch the left over bombs. Get the spiny ones first.
Wave 63
Keep your head down and watch the safe zones, the dogbots will soon
disappear.
Wave 64
Get the spiny ships before the bombs reach you.
Then, as in the previous wave, blast away.
Wave 65
Just like before, get the birds first, then stick to the safe zones.