YMMV / The Guest

• Awesome Music: The movie is full of synthesizer-heavy, '80s goodness courtesy of composer Steve Moore.
• Creepy Awesome: David. While he's a creepy character even when his only problem is that he seems off, it's impossible not to be enraptured in Dan Stevens' charismatic performance.
• He Really Can Act: Dan Stevens, best known up until this point for his role in Downton Abbey, as David Collins the sociopathic, deranged super-killer.
• Hilarious in Hindsight: This wouldn't be the last time Dan Stevens plays a dangerous man named David.
• Magnificent Bastard: David Collins is an immensely charming soldier home from war and hell-bent on "taking care" of the Peterson family through any means necessary. Transformed into a super soldier by the government, David uses his enhanced strength and speed to effortlessly kill and brutalize anyone in his way, humiliating bullies targeting Luke Peterson and murdering the boss of Spencer Peterson to get the man a promotion. Effortlessly weaving his way into the Peterson house and their entire neighborhood as a beloved and polite man, David soon enough reveals his true colors after his programming to protect his identity from compromising kicks in, causing him to begin murdering the entire Peterson family, even while showcasing his regret. When beaten after wiping out an entire military squad sent after him, David praises Anna and Luke's efforts in stopping him, and still manages to get away with his life intact when the smoke clears.
• Spiritual Successor: It's a thriller about a Sociopathic Soldier who was abused and then abandoned by his government, and proceeds to go on a rampage through a small town, with his former handler sent in to stop him. In short, one could see it as a more faithful adaptation of David Morrell's novel First Blood than the actual film adaptation thereof (albeit given a Setting Update to The War on Terror), which famously made John Rambo far more sympathetic and something closer to an Anti-Villain at worst.
• The Woobie: By the end of the movie, Anna and Luke have basically lost everything. David has murdered their parents, destroyed their home, and ruined their personal lives as well. Two of Anna's closest friends are killed by David, who then frames her boyfriend for one of the murders. Anna herself barely survives David's attempts to kill her as well, and Luke was forced to fatally stab David, whom he was very loyal to and thought of as a friend and (by implication) a surrogate older brother. And the ending implies that David might still be after them, since he's apparently very hard to kill.