Image copyright Getty Images Image caption Chris Christie dominated in key moments

The Republican presidential debate was a bit like the final act of a horror film. The monster had already eaten half the teens at the summer camp, and those left were wondering who was next to go.

Some of the candidates seemed like they were ready to fight.

Some of them looked like they wanted to hide or run.

And Ben Carson acted like he didn't care whether the monster got him or not.

FIGHTING

Chris Christie - The New Jersey governor didn't waste any time going on the attack during the debate. He's bet his entire campaign on a strong showing in New Hampshire, and Marco Rubio's recent surge in support here could deal his campaign a mortal blow.

At the first opening he launched into a blistering attack on the Florida senator, accusing him of lacking experience and constantly resorting to a "memorised 25-second speech that is exactly what his advisers gave him". When Rubio tried to launch into another set response, Christie went for the kill.

"There it is," he said. "The memorised 25-second speech." The audience howled in support of Christie's insult, and Rubio began to sweat.

The debate may have gone on for another two hours but the day-after headlines were written with that exchange.

Final reviews: Christie was looking to draw blood on Rubio and he did. He'll get good reviews from the media for his performance, but sometimes the candidate who delivers the killer shot isn't the one who benefits the most

Jeb Bush - Christie isn't the only candidate threatened by Rubio, who also presents a clear threat to his fellow Floridian, Bush.

Although the former governor was more than ready to launch his own attack, it seemed superfluous after Christie did such a thorough job eviscerating the senator.

"Marco Rubio is a gifted, gifted politician, and he may have the skills to be a president of the United States," Bush said. "But we've tried it the old way with Barack Obama, with soaring eloquence, and we didn't get a leader, we got someone who wants to divide the country up."

Bush also had an interesting back-and-forth with Donald Trump on the topic of eminent domain (compulsory purchases by the state), in which he was buoyed by an audience that began booing when Trump slammed Bush for trying to act like a "tough guy".

"How tough is it to take property away from an elderly woman," Bush shot, in reference to a case in which Trump attempted to use the government to help him acquire property for one of his Atlantic City real estate projects.

Final reviews: Bush finally seems to be displaying a bit of a backbone. His performance was good enough that he could end up benefiting from Rubio's bad night.

Image copyright Getty Images Image caption Bush hugged his wife after a solid performance

John Kasich - It was a good night for former and current governors all around. Kasich generally stayed above the fray, with Christie doing the dirty work of bludgeoning Rubio, and made one of the most compelling arguments for his candidacy of his entire campaign.

"I've learned that, what makes things work, what gets the economy going, not just in Ohio, but in Washington, and it's three things," he said. "Common sense regulations, which we have, lower taxes, which we have... And thirdly, a fiscal plan to balance the budget."

At one point Kasich even seemed to be channelling his inner Trump, telling the audience that if he's elected president they should go out and buy seatbelts.

"There's going to be so much happening in the first 100 days, it's going to make your head spin," he said. "We're going to move America forward. I promise you."

Final reviews: Like Christie, Kasich is betting everything on New Hampshire. He's pitching himself as the only candidate with both Washington experience and a record of achievement as a big-state governor. If the debate damaged Rubio and made Christie look like a bully, it could be Kasich who comes out the beneficiary.

HIDING

Image copyright Reuters Image caption Trump was booed for telling Bush to be quiet

Donald Trump - For once, the Donald wasn't the centre of the debate. He had his brief fight with Bush over eminent domain, but for the rest of the time he was largely on the sidelines.

He was given an opportunity at the outset to rekindle the warfare with Ted Cruz that broke out two debates ago, and he took a pass. His trademark bluster was largely absent - or, at least, greatly overshadowed by the show that Christie put on.

Trump issued his now traditional boast that he put immigration and border control on the Republican agenda - a statement that, at this point, no candidate seemed interested in challenging.

He could have finished higher, but the audience's booing to some of his remarks put him on the defensive. He tried to explain that the boos were from establishment Republicans threatened by his rise, but his attempts only made him look weaker.

Final reviews: Given that Trump continues to be the frontrunner in New Hampshire polls, keeping his head down and his powder dry may have been the best move. If nothing changes between now and Tuesday's vote, he's poised to win the state's primary and regain the momentum he lost with his second-place finish in Iowa.

Ted Cruz - While it wasn't a renewal of the love-fest that they shared earlier in the campaign season, the Texas senator also declined to aim barbs at Trump. He only criticised the billionaire indirectly, saying that voters would assess all the candidates on their judgement and level-headedness.

Cruz was knocked a bit off balance early, however, when asked to explain the actions of his staff on caucus day in Iowa, when they spread rumours that Ben Carson was suspending his campaign. Carson and Cruz were competing for the same evangelical voters in the state, so Cruz's team perhaps hoped they could benefit from the news.

"When this transpired, I apologised to him then, and I do so now," he said. "Ben, I'm sorry."

Cruz's best moment likely came when he discussed his half-sister's death of a drug overdose.

"This is an absolute epidemic," he said of drug addiction in the US. "We need leadership to solve it."

Final reviews: Like Trump, Cruz was a spectator for the night's biggest fireworks. Although he's competing in New Hampshire, his victory in Iowa allows him to survive a less-than-stellar finish in a state that isn't as interested in his evangelical conservative pitch. He'll be ready to make another move when South Carolina holds its primary in just two weeks.

FLEEING

Image copyright Getty Images Image caption Rubio (left) cut an isolated figure, attacked by all sides

Marco Rubio - Rubio was the man to beat heading into Saturday night's debate, and a beating was what he took.

He may have thought he was prepared for the coming onslaught, but his smooth responses played right into Mr Christie's hands. On several occasions he repeated exactly the same line, illustrating the New Jersey governor's points with painful effectiveness.

When the topic turned to foreign policy and news of a North Korean missile launch, Rubio continued to appear rattled. He regained his footing later in the debate, with a passionate defence of his views on banning abortion even in the case of incest and rape - but by that time the damage was done.

"It's a difficult issue, because it puts in conflict two competing rights," Rubio said. "On the one hand is the right of a woman to choose what to do with her body, which is a real right. And on the other hand is the right of an unborn human child to live."

He said he chooses to err on the side of life.

Final reviews: Mr Rubio was poised to consolidate mainstream Republican support with a strong showing in the New Hampshire primary on Tuesday. He gave his weakest debate performance of the campaign Saturday night, however, and if it costs him at the ballot box, he has only himself to blame.

EATEN ALIVE

Ben Carson - The retired neurosurgeon's debate started off with confusion. Although his name was called, it was drowned out by applause. The result was Carson stood behind the stage curtains, with cameras on him, as the other candidates strode onto the stage one-by-one.

It didn't get much better for him after that. He once again was absent from the conversation for long stretches of time. In his closing statement, he told the audience: "I'm still here, and I'm not going any place either."

It's never a good sign when you have to assure everyone that you're not about to drop out.

Final reviews: Although the rumours that Mr Carson was ending his campaign after Iowa on Monday proved unfounded, he did head home to rest before finally returning to campaign in New Hampshire on Saturday. He may still be in the race, but he doesn't seem to be trying very hard any more.