I think you would be hard pressed to do much better than Infinity. It is a game for modern-near-future combat in game design but incorporates a lot of science fiction special rules in it.
One of them is TO camo, which makes models almost invisible to the enemy. You need to detect them before you can shoot them, then you suffer a penalty to shooting them. The rules for close combat are pretty easy and reasonable.
Plus the rules are free on their website along with stats for all the armies so you might be able to find something to proxy predators already in there.
infinitythegame.com