I thought Trump did poorly.
Trump missed a chance to go after Hillary about Libya, especially her statement "we came, we saw, he died" in which she bragged about killing Gaddafi. Libya erupted in a civil war following that event and terrorists are running the country. Well done Hillary.
Trump also missed a chance to attack the Clinton Foundation.
Trump faced three gotcha questions, and Hillary zero. On those grounds, the debate was quite a bit biased. Still, Trump missed a golden opportunity on some of the questions.
On the nuclear war issue, Trump should have commented "Hillary has supported every war every time."
On the Birther issue, he simply should have stated, "I changed my mind. If we saw the birth certificate sooner, I would have changed my mind sooner. Obama will be gone in a few months, why is Obama's birth certificate even relevant now?"