Get the spiny ships first, then there won't be any trouble with faster bombs, besides, they're easy to kill.
Wave 57
It's nearly impossible to get the power-ups before killing any aliens
in most of the waves to follow. I just blast away and pick up the power-ups
as they fall.
I just picked up the power-up, note the lack of aliens...
And the last power-up, on to finish the rest off.
Wave 58
Get the birds first, I find it easier to watch the bombs when there's
only one colour.
Wave 59
Once again, get the spiny ones first.
Wave 60
And again, as you can see, the two shots of mine, left over from the
last wave, are going to get the bird before I have a chance to get the
power-up. So, just blast away and pick them up as they fall.
These power-ups should be pretty straightforward to pick up. Just be
careful of the bombs between them.