Terrifying and disturbing, The Wailing keeps you on edge for two and a half hours, mostly because you've little idea what's really going to happen.
It's unpredictable, but not off-the-wall, shocking, but not gratuitious, and deadly serious, but not without lighter moments. It's perfectly balanced.
It may be over-long by about twenty minutes, but it manages to sustain its runtime with great engagement. Its characters are ordinary folk, nothing extraordinary about them, and you identify with them greatly because of it. It's refreshing to see.