The epic poem Beowulf gets an imaginative, low-budget workout in this 2005 Icelandic feature by Sturla Gunnarsson. Shot along Iceland’s rocky southern coast, it wisely forgoes computer-generated imagery to reenvision the monster Grendel as a giant troll (Ingvar Sigurdsson in close-ups, Spencer Wilding in long shots) living in the mountains and nursing a grudge against the aging and addled King Hrothgar (an excellent Stellan Skarsgard). The strapping Beowulf (Gerard Butler) is torn between the two, and the tension between pagan and Christian thought in the poem’s text is explored through two added characters, an evangelizing Celtic priest (Eddie Marsan) and a pagan witch with an American accent (Sarah Polley). The movie drags somewhat in the middle but comes charging back with the arrival of Grendel’s mother. R, 103 min.