The Ruins

This was a good book. The monster was great and the atmosphere was even better. The only thing was I couldn't care about any of the characters. The only character I even came close to giving two shits about was Mathias. This group of protagonists were just the dumbest group I've ever read about. While I was reading this, every decision they made just kept getting dumber and dumber, and by the time they got stuck on the hill,  
I literally just didn't care at all. 
To me personally, I just saw it in a way where the characters almost went out of their way to get themselves stuck in the situation they were in. But hey, if they had been a bit smarter, there wouldn't really be a story worth telling. 
I would still recommend this is caring about the characters isn't an issue for you. The book was really fun, and again, the atmosphere was top tier