CONTAINS SPOILERS, LIKE I CARE
And still they come: yet another tedious teen horror movie in which a bunch of obnoxious scumbags don't get killed nearly bloodily enough to raise the slightest flicker of interest in what happens to them. As is so often the case, the filmmakers don't know how to write any interesting and sympathetic characters, so they make one of the group so morally repugnant, so vile and hateful, that everyone else seems tolerable by comparison. And in this instance we have a loudmouthed and arrogant prick so thoroughly despicable that he actually becomes more of a human being when he's suddenly possessed by Satan. Admittedly the character does have reasons for being a thundering arsehole, but even so you shouldn't be compelled into siding with the smallest dumbass in the room as the least worst option.
Four teens are so boneheadedly idiotic they decide it would be a brilliant idea to hide out in the local morgue and perform a seance so they can prove the existence of an afterlife. One of them brings a video camera along because he's a delusional halfwit who thinks he's going to make the greatest student film ever, one's a violently shouty imbecile who thinks it's a hilarious prank to lock one of the girls in a freezer full of corpses. One of the girls is a Santeria prietess, and the other is a born-again Christian with a painfully melodramatic backstory, and all of them are dumb as a plate of cold tripe and deserve to die at least twice. Inevitably their seance goes wrong, leaving the door to the spirit world open so the violently shouty imbecile gets possessed by the Devil and kills the camera guy....
Seance: The Summoning is billed as "From an executive producer of Hellraiser", which is technically true (Christopher Webster was EP on Hellraiser and producer here) but meaningless as he's not the creative voice of the film so it's like billing The Cannonball Run as "From the producer of The Godfather". You might as well bill it as "From the Dialogue Editor of Ski School II" for all the relevance it has. It makes no sense: the Devil is eventually taken down by one teenage Christian whose soul is damned anyway and one girl who converted to Christianity about ten minutes previously, and at no point do they ever consider that they never did bother to close the door to the spirit realm. Boring, stupid, and pretty much entirely worthless; if this is the best you can do it's probably better for all mankind if you give it up now, and go and open a carwash or a tapas bar somewhere.