I know there have been terminator games in the past. Loads of different attempts to bring the films to life, mostly where you play someone fighting a terminator (if it's faithful) or lots of terminators (if it's taking liberties). The best games, like Future Shock, don't try to adept the film literally and are set in spin-off universes. The worst, like the Virgin Sega game, have you being Kyle Reese, repeatedly and futilely trying to stop the machine.
The problem is that having one indestructible foe for a whole game does not work as a fun game mechanic. What would be good, IMHO, is a rogue-like sand-box cityscape, with you as the terminator, tele-porting back to 1984 and being charged with the assination of: [insert name here].
That's pretty much it. All you know is a name, and you've got a whole city to explore. You could just kill everyone, you're bound to get the right person eventually. Track down your target - unlike Hitman, they'll probably be entirely unguarded - and kill them with one shot. A lot of rogue-likes aim for spectacular failure. What about one where you're almost guaranteed to win, but the time loop paradox succeeding generates means you just get sent back to the start? See, it even makes sense.
The City and its inhabitants are randomised, as are the stats of the soldier sent back from the future to stop you. He'll fail of course; he's only human. But he might give you a run for your money, provoking you into epic car chases, fire-fights with increasingly desperate authorities, fun, emergent gameplay that's all ripped off GTA. The Kyle Reese character exists only to put the challenge in, to be the spanner in your works, that leads to all sorts of madcap schemes. And if he gets the target on the back of a motorbike and rides off into the night, how will you find him? With detective skills and by any means necessary.
I think this has got legs. Anyone fancy making it?