Nothing particularly awful, nothing particularly brilliant. Lots of elements felt vaguely derivative enough to come across as tired, admittedly probably without being direct influences. Still, who wasn't reminded of either Westworld or TNG's The Hunted while watching?
Having said that, I thought it was a much better story
than last week's Dinosaur claptrap, though far weaker than the opening Asylum episode. What it really needed to lift it out of the mire of mediocrity was a really killer psychologically-explosive exchange between the two Doctors about death, guilt, morality, justice & personal responsibility. After all, they both had quite a unique perspective on making choices that impacted on wars. I thought we were going to get it at one point but the conversation at night in the sheriff's office just drifted into nothingness. Shame, really.
On another note, I've never really warmed to Amy & Rory anyway, but I really thought they didn't need to be in this episode. The only thing they had to do was Amy's cringeworthy speech to the Doctor stopping him from surrendering the other doctor to the cyborg. The writers could have given the ethical essence of that speech to the Sheriff and it would have probably sounded less forced coming from a character so embedded in town's story rather than from a companion.