«But not another tunnel's end? (Now you have more than one tunnel!) I think you meant to say that he can see only one end of the tunnel»
Yep, I even considered "only one the tunnel's end", but it doesn't sound right as well...
«To my ear, ancient and factory don't go together.»
The game's setting is far future, and the hero crash-lands on a planet where he finds this ancient weapons (military) factory, ancient gliders and ancient laser guns... And when he finds a helicopter it is as amazing to him as meeting a dinosaur.