Among the worst endings?
I wasn't expecting or hoping for a happy ending, so I wasn't disappointed or surprised in that regard. However, the last ~20 minutes were downright comical. It's an amusing movie throughout, but the end transitioned to a farce.
The details of the killing of Madeline were absurd and difficult to believe. The punitive tongue removal was totally out of character for the priest to order, not to mention ahistoric. The choking on the crucifix was--need I go on?
I don't regret spending a few hours with this film, but it left an acrid taste in my mouth to say the least.