Style over substance.
Great period setting, the guy playing the police captain was perfect for the part... and the setup was intriguing. But once he goes into the cave... meh! Like they didn't have a real idea, just the setup (see Yellowbrickroad).
Also, the 'girl' was just mundane pretty... nothing weird or unearthly about how she looked... needed someone 'scary pretty'... Tilda Swinton or Amanda Plummer-ish.