I watched this pretty much at random after hearing about it from a guy at work. Generally, I think the film is pretty decent with some good suspense, but I can't help but feel I lose interest the closer we get to the conclusion.
The atmosphere throughout the film is pretty top-notch, and is helped along by the moderately small cast (three, maybe four important characters in whole). Story-wise, Delirium's not the most original movie, but it is tense, and portions leave you wondering what is and isn't reality. I also have to give props to the cinematography - while there were more jump scares than I'd have preferred, like I said, there were some pretty tense and atmospheric scenes, and those were done right.
Topher Grace does pretty damn well as a man suffering from both a tragic past and mental problems. Solid performance, and even his facial expressions stood out, so there's little to complain about there. Patricia Clarkson's character was certainly iffy, but her acting itself was perfectly adequate. Genesis Rodriguez was pretty impressive in her role, and rather cute to boot. Lastly, Callan Mulvey certainly possessed a threatening feel to him, but I sort of felt he came across as a bit generic.
It's the finale that I had the most issues with, and I can't even quite explain why that is. It's not really rushed, but it sort of answered things almost too cleanly, which I know sounds an odd gripe. I just think I'd have liked a bit more mystery near the end than what we got. It doesn't help matters that much of what we got at the end was highly hinted at before, so none of it really came as a surprise. As for the final scene, I can only hope things work out for the best regarding Grace's character.
The two highlights of Delirium are the tense atmosphere and Grace's solid presence. While neither fully makes up for the ending, I do think that the film is generally pretty okay, and you could certainly do worse. As it is, it's probably around average, but I'll boast it a bit due to the factors I rather liked. One last thing worth noting - Dennis Illiadis, the director of this film, also did The Last House on the Left remake from 2009, so I'm happy to see that he's both still operating in the genre and making better films. 7.5/10 (rounded down to 7/10 to fit site's format).