This is a very interesting game considering Bethesda's later history. It is their first ever attempt at an open world game, years before the famous Elder Scrolls series. And it is very much an indicator of things to come, because it is also an incredibly unfinished, buggy, overly ambitious, nigh-unplayable hunk of glorious junk that has such a great concept that, as you play it, you find yourself longing for a better version of the same game.
In this case, it is a complete simulation of the famous 1984 Cameron film THE TERMINATOR. You can choose to play as either Kyle Reese, in which case your object is to defend Sarah Conner from her robotic attacker, orhimself, in which case your object is to find and kill Sarah Conner.
Your arena is a roughly accurate 3d map of Los Angeles, presented in real time 3D - in 1990 - programmed lovingly in raw assembly to get the speed necessary. Of course, all the buildings are basically colored blocks, and it's a beautiful sunny day out - not exactly the lighting conditions one thinks of when they think of.
And what can you do in this arena? Well, a number of things. You can steal cars, shoot civilians, rob stores - half the stuff in the stores is useless, humorously including condoms in the drug stores (I guess for the purposes of the plot Reese should stay away from those).
But the problem is, as said earlier, it is overly ambitious and doesn't really feel complete. The controls are straight-up bizarre (though that can be somewhat excused due to the fact that nobody knew how to control a first person game back then, Ultima Underworld also suffered from this problem). There's also not enough to do, and the things you can do can be awkward. They have a mechanic where as you due illegal acts, the police will start hunting you down - but they're way too forceful (think Daggerfall or Arena, “Halt! Halt!”), which can ruin the experience. This game no doubt took a long time and a lot of people to make, but like the rest of Bethesda's open world experiences, it feels like it needed a bunch more people and at least a year's more work.
All in all, I couldn't recommend it as anything more than a curiosity, to see a sign of things to come for a now-famous developer.