Cuckoo (2024) review

Sullen teenager Gretchen (Hunter Schafer) goes on vacation in the Bavarian Alps with her biological father Luis (Marton Csokas), step-mom Beth (Jessica Henwick) and nonverbal step-sister Alma (Mila Lieu) and they stay at a resort operated by König (Dan Stevens), except things become weird when Gretchen is chased after by a woman dressed like Kurt Cobain and she tries to leave with her lover Ed (Àstrid Bergès-Frisbey) ... and then it turns out König thinks of himself as a mad scientist (or something to that effect).  It's trying to be a "horror" movie, but nothing really works in its favor: Gretchen is a deeply unlikeable lead character, the "special effects" involve the screen wobbling like cheap plastic, most of it fails to make much (if any) actual sense and the last scene, where Gretchen escapes a shootout with Alma, is so atrocious even Dario Argento would have thrown it out.  Since it barely attempts to be scary, the only sliver of joy one can get from it is watching Stevens ham it up (while speaking German) and play a magical flute.