Same game just less of it. The base mechanics are just copy pasted from F1 into F2.

F1 gives a more desolate post apocalyptic vibe while to me F2 feels like the point where civilization is finally starting to retake the wasteland.

The difficulty is far lower mainly since you get started with supplies so typically your equally armed or better armed then the starter encounters. There are far less random encounters and their difficulty is linked to your luck stat so if you have a decent amount of luck you'll probably not run into any of the very hard ones.

Unarmed is pretty mediocre the whole game, since you start with a gun and can get better guns pretty quickly. It's still possible but it's exactly like F2 where you just start taking aimed shots at the eyes until everyone is blind.
There's also no HtH evade so you don't gain extra dodge so enemies are slightly more accurate.

Combat difficulty is an order of magnitude lower, too, with top tier enemies having sub 80 HP. It's a very, very easy, and short, game.