The 10 candidates on the stage, with another 10 debating tomorrow, had around 10 minutes maximum to make sure they stood out. Some triumphed, some failed.
The candidates were: Cory Booker, Beto O'Rourke, Elizabeth Warren, Julián Castro, Amy Klobuchar, Tulsi Gabbard, Tim Ryan, John Delaney, Bill de Blasio, and Jay Inslee.
Ms Warren is the frontrunner of those names when it comes to the national polls, with Mr Booker and Mr O'Rourke the other candidates with solid name recognition.
Here are our winners and losers from the two hours of questions, impassioned statements and squabbles.
The senator from Massachusetts was the person to beat in the debate and would have expected the other candidates to come after her. Getting through the two hours without a major slip or spat would have been enough.
But Ms Warren did more than that. She has set herself up as the candidate with plans, putting out more policy plans than almost anyone else among the more than 20 Democrat candidates. That showed in a strong first hour that involved questions on her favourite topics - healthcare and the economy.
She has called for "structural change" in many departments and that message was relayed strongly. Other candidates will be bemoan her airtime, the third most among the candidates, and the fact she was given the last word.
A quieter second half to the debate might be picked up by some - but giving other candidates a chance to fight with each other for the limelight left her looking quite stately.
The New Jersey senator spoke for the longest amount of time, 10 minutes and 55 seconds, but he used it effectively.
He was involved in most of the topics and had one standout moment talking about violence against the LGBT+ community and particularly.
"We do not talk enough about transgender Americans — especially African-American trans Americans," he said to a cheer from the audience.
Mr Booker had decent name recognition before the debate and will not have done his standing any harm.
The former San Antonio mayor had been running under the radar - but had a very strong night.
He managed to carve out more than nine minutes of speaking time and made sure he took advantage of an emphasis on immigration for a large section of the debate.
Gained a cheer for his quote that the the photograph of the bodies of Oscar Alberto Martínez and his 23-month-old daughter, Angie Valeria who drowned crossing the Rio Grande should "p*** us all off".
Painted President Donald Trump as cruel over his border policies in the wake of that and made former Texas Congressman Beto O'Rourke look slightly foolish when the pair clashed over what to do over immigration at the southern border.
The centrist candidate sounded level-headed throughout the debate, whether she landed enough big hits is open to question - but she got a couple of quips in about Mr Trump's unsuitability for office.
She also scored a big point in taking Washington Governor Jay Inslee to task in trying to claim credit over legislating to protect a woman's right to choice an abortion in his state. Ms Klobuchar said that there were "three women on the stage" who had fought hard to protect those rights.
Tim Ryan and John Delaney got in a decent amount of airtime each - around seven minutes - and scored some decent soundbites on immigration and climate policy.
Mr Inslee's major issue is global warming and much of his four minutes of talking was taken up with discussion of it. He will take that as a win.
The former Texas congressman, who shot to national attention during his close-but-no-cigar run for the Senate in 2018 in a deeply Republican state, had a bad night.
He has been able to raise a lot of money from donations, but was out of his depth on policy here and sounded forced.
Speaking Spanish was a good way to reach out to the Latino vote - but being beaten on immigration issues by Mr Castro was not.
He needs to start looking like a well-rounded candidate to lift his sagging poll numbers. But he did not do that here.
Bill De Blasio
The New York mayor wanted to show off his policies on wages and gun control to a national audience. What he actually did was repeatedly talk over others and failed to make much of an impact.
Will have done his likeability with voters some harm.
Ms Gabbard was the most searched candidate on Google during the debate, and that is likely what she would want. Pushed her military credentials when speaking about foreign policy which should win some fans,
However, pivoting questions to her military record when it did not call for it, such as when being asked about the gender pay gap will have left a sour taste.
The debate format
It was always going to be difficult for candidates to make inroads in a format that had 10 people on stage on each of two nights.
Policy was generally front and centre, which will have pleased party leadership, but in reality we will not get a true idea of candidates and their ideals for another few months.