The first half, with the bridge scene the highlight, is better than the second but the latter does showpiece the terrific work of the makeup department.
Whilst the screenplay is far from convincing you overlook its weaknesses in the cause of entertainment and root for Ingrid trying to hold things together plot holes and all.
The lead Christensen is not much chop but thankfully it is not an actors film and the special effects, the design work, and the creature people make it all worthwhile.