Not many visual cues. No VASI, not much except for the platform or drilling rig, and the view is different every time, because the approach direction changes depending on the wind direction. You may not even see the helideck when you break out, not until you're very close and turning around the obstacles to find it. The approaches are based on GPS, which is much better than the way we did it long ago, LORAN. The precision is at least an order of magnitude better, but it's really not that different, since you also use the weather radar in ground mapping mode, so finding the rig isn't much of an issue. The final approach is done by eyeball, no approach aids on any platform I've ever landed on. It can be demanding, especially at night, but that's why we make the big bucks. If you're challenged by sarcasm, disregard the last few words of the previous sentence.