A great sense of nervous tension. Something that a sequel would find hard to live up to; Predator 2 fell short of that, for me.
Yeah but it's not what they went for in P2. We already know what a Predator looks like and what it can do, so there's no point in trying making the viewer feel tense or whatever. We know the threat.
Instead of the mystery derived from the unknown (cause as I said before, would have been pointless), they went for the kind of mystery you find in investigation media, as you watch Harrigan and his team trying to figure out what it is that they're dealing with, while at the same time, giving the Predator more screen time (thanks to a higher budget no doubt) and focusing more on him, and adding a lot to the mythos, like its arsenal (the iconic Combistick, Net Gun were introduced here, and the Smart Disc too, although the AVP movies will later reduce it to a more generic big shuriken), the Predator architecture, a deeper insight into their culture and habits.
Predators did that too, although kinda playing it safe by referencing the first movie WAY too much. That's why I want Shane Black to take all that into account and flesh things out more and expand on what the previous movie established. That's what any good sequel should do.