Then the third vision mode of the pred detects electrical output. This makes aliens easy to see but is very hard to detect humans. Then the fourth mode which is the best and the one I used the most can detect humans, aliens, and predators. It is very good at detecting predators and also for navigating in the dark. To top it all off the predator also has a zoom mode.
Conclusion Buy it.
Even if you hate the movies. And the no-save game feature. Fox just wanted to make it hard, scary, and fun.