If you can't attack after one of your ships gets destroyed, you need to click to select one of the other ships. This is caused when ship you used before ending turn gets destroyed.
i got to the lvl 34 before giving up. it's just so annoying! By the way, lvl 30 isn't that hard once you find good route. Here's a hint: At start run right and airjump just under diagonal sawblade. if done right turret waiting at bottom should fire and miss and give you time to jump to the platform. Rest is just jumping and hoping to dodge bullets.