Estatica,
Xenomorph,
15 years ago
Personally, with my own opinion that will be forgotten eventually, I can see some things that are clear to me.
The predators, for instance, seem to me to be like the highly-advanced safari-hunters of the universe, killing sentient beings for sport with high-tech weaponry that, I suppose, the marines would probably develop something of such power given enough time. Generally accepted rules of the hunt by the species as a whole, though the civilization as a whole being sparse in locations and only in large groups when special help is needed from the homeworld when a dangerous crisis begins.
I'd also think that their race would have augmentations and armour properties that made the race's strength comparable to an alien. Additional strength, reflexes, sight and the ability to camoflage itself are the things we know it can do from the original movie, though I'd also assume that tair armour would increase their constitution among other things that would help in the hunt.
As for the aliens, I'd think they would be much stronger and faster than humans, and probably as strong, or stronger, than a predator. The queen is the ruler of the local population of aliens, directing them via a form of telepathy. Aliens without said queen would ahve to rely on pheremones, snarling, grunting and most likely other forms of communication to direct eachother. A lone alien in space, for instance, would be the singular hunter - using stealth and percision to hide and strike when the time was right, much like the predator. With a queen directing them and with a large amount, they would resort to swarming the enemy with a sheer mass of numbers, strength and speed. These two theroies can be seen in the two movies, I think - Alien with the first, Aliens with the second. Without the queen to direct the drones to bring back living people for impregnation, their only need is to kill, devour and feed.
And, of course, there's quite a few different types of aliens, I'd think. We know there's such types like runners, predaliens and drones, but there's most likely other kinds of types we down know about. And as for the Praetorians, I think they're visible in Aliens for a brief few moments when they come walking out of the corridors, attempting to surround the two main characters. In that sense, I'd say they were royal guards of some sort - protecting the queen and following her orders more precisely than the drones, runners and predaliens. Drones being the cannon fodder, runners being the scouts and assassins, and predaliens soaking up damage and dealing it out like their species' tank. I'm willing to think that there's other species of aliens like we've seen already, just that our poor marines haven't encountered them yet.
As for the Marines, I've not much in the ways of view on them - most likely, they're like the result of the United States of America taking over the world and spreading into space - no offence, Americans. Using weaponry we know from today, though developed and advanced through time when greater materials wew discovered and promptly put to use. We've got the machine gun, a grenade launcher, a rocket launcher, and other such things - and they've most likely kept to those methods because they usually work.
And there's the end of my speculation.