Young couple get lost in the bog and encounter deadly night creature from the ancient past.
Good, pure horror. Simple set up, no fancy backstory, and constant threat from the shadows with lots of setbacks for the heroine. Maybe a couple of questionable things in the final act - three sources of alcohol/kerosene? Jump scares were variable.
One thing I loved about this was the dialogue between the couple in the car - authentic and amusing, really likable characters. Both parts well played, and later on the actress kept it natural, no exaggeration. One thing with Irish actors, though, is they sometimes rush their lines - I missed a few, but the pace and logic were good enough for me to carry on.
The creature remained mysterious, which was good. Lots of different sources of light in the dark, but I didn't really get the contrast. May be a digital thing. And the smashing of the headlights should have been more gory.
Sound was well judged - in the opening sequence just wind and breath until the attack - and the music kept up the tension without overwhelming.