“Spiderhead” (*1/2 out of four) was an empty-headed suspense melodrama set in the not-too-distant future in which prisoners are offered to volunteer as medical subjects to receive a shorter sentence; one such prisoner (Miles Teller) volunteers for a test but soon begins to question the reality of his emotions and the true intent and motivation behind the administrator (Chris Helmsworth) behind all this. A disappointment from director Joseph Kosinski who also directed “Top Gun 2” (which also stars Teller); story is muddled and obtuse and it would help if you actually cared about any of the characters. George Saunders co-wrote the script and adapted his own short story so less sometimes really is more.