The stuff I was talking about was more.... I don't want to keep using the word radical but its meaning fits the bill.
For instance. Alien introduces us to the Alien and its lifecycle. Awesome and mind-blowing. Aliens introduces us to the Queen and what the Hive looks like, also awesome and mind-blowing. Alien3 shows us the runner, which, at the time, was, well, Mind-Blowing. There was no way to know that a dog would birth that type of alien. For all we knew at the time, it was going to look like the ones in Alien or Aliens, you know? Alien3 also showed us the Queen embryo and Super Hugger. Radical new concepts.
The Prætorian is just an extension of the Queen-Burster concept, that a Queen grows differently. The Predalien is just an extension of the concept introduces in A3 that the host plays a large part in what the Alien looks like. The last film to have a radical new alien concept was actually Requiem, with Chet's Reproductive system. The games don't really have something out there like that.
I'm not saying they haven't introduced anything new to the Aliens. The games are, after all, the medium that canonized the pyramids and the tail barbs. Prætorians and Predaliens showed up first in the comics though, IIRC.
Look at the Preds now. Predator showed us the Predator, his hunting, and some of their tech. Predator 2 showed us some more tech, yes, but also showed us what their ships looked like, a bit more about their culture, and showed us the trophy room. AvP taught us even more about their culture, as well as their relationship to the human race. Requiem showed us a frigging Predator planet, along with a new concept for the Preds, that of a "sweeper" that cleans up messes. They're not all just hunters then. Predators introduced a new race of Predators, and showed us radically different tech and methods than we'd seen in the last 4 films. We got to see Hounds, Bird bots, variations on their tech, and learned that they have freaking game preserve planets.
The games have given us... some new Pred tech. Other than that, I think Concrete Jungle's assertion that they are a Nomadic race and that a good chunk of WY tech is reverse engineered or salvaged from Pred tech are the most out there concepts that have been introduced by the games for our hunters.