Body Harvest was an Open World Third Person Shooter developed by DMA Design (now known as Rockstar) exclusively for the N64. You can read my review for it here:
I loved the game and still play it regularly. The wave based attacks and the fact that the Aliens can actually kill all of the civilians and win gives the game a sense of tension that is very rare. Also the fact that the five levels are scored gives a great incentive to replay in an attempt to beat yourself. Again, coupling this with the fact that the aliens can win only adds to the tension. Also the game is one of the only open world games I've played that have fuel for the vehicles you use. This means you have to constantly manage your fuel, especially as vehicles can play a large part in any boss fights or when you attack the shield processors.
Though it certainly seems highly unlikely that Rockstar, or anyone for that matter, would revisit the game and make a sequel, I genuinely believe that a sequel or remake could be fantastic but there are a few things I would add to the formula just to make it that little bit more awesome.
Online and Offline Co-Op
If you could play this game with three other people it would be incredible. You could either each go after an individual shield processor or you could team up and take on one together. Online would be great but I really miss the days when co-op meant split screen and not just online. If I could play the original Body Harvest with Alan playing as another marine then people would never see us again because we'd just be massacring Aliens.
Body Harvest was around at a time before cover systems were popular but if a new entry had slightly more fleshed out environments then a cover system that drew inspiration from a game like Gears of War would add some tactical depth to the game.
The basic premise of Body Harvest is awesome, you're a super solider whose job is to save the world from an alien invasion, but there is no mention of the turmoil or drama such an invasion would cause. Stories about the human's suffering and things like that could add a layer of emotion and depth to the game that would really improve the overall experience.