AN IRISH EXORCISM is a found footage exorcism/demonic possession horror movie (a sub-sub-sub genre, apparently) which follows a two-member documentary team that attempts to film an exorcism on a possessed Irish girl attempted by two priests.
One of the strengths of this movie is that is clearly explains the background on exorcisms and some aspects of how they are actually carried out, something which other such movies generally leave out. The biggest strength is that this movie takes a real risk by leaving the actual exorcism largely to our imaginations, as the camera only shows after effects, and pulls it off, at least to some extent.
I believe that these types of movies, if they want to have a chance at being memorable, have to introduce a novel element which sets them apart from other movies in this triple sub genre. Unfortunately, providing a documentary approach to the background and preparation of an exorcism and then leaving it out of the movie was not enough.
The low budget is pretty obvious, but the story chugs along reasonably well, except for some irritating contrivances. For instance, more than once the camera is supposedly recording the participants in a clandestine way even though they would just need to look up to see it. Or, at one point the main priest takes on a former medical student in lieu of a practicing physician, something which practically screams "plot contrivance".
The most disappointing part is the ending, which caused what I would have considered up until then a very slightly above average found footage film to stumble. The ending is at least partially predictable, yet fails to tie things together, a deadly combination for a movie's satisfaction factor.
There are better found footage exorcism/demonic possession movies, such as THE LAST EXORCISM (2010), THE POSSESSION OF MICHAEL KING (2014) and THE DEVIL'S DOORWAY (2018), which is incidentally also set in Ireland.