[viccis]

My favorite high tech AI was Crysis. Might have been an update after it was originally released. The enemies will aggressively attack but then get quiet after you've taken cover. Eventually you'll realize some of them are flanking you while others keep suppressing fire on you to stop you from moving. You can hear them yelling to one another. Very cool touches.

[tmtvl]

That reminds me of First Encounter Assault Recon, where the AI had fairly simple rules, which worked well with the level design to make the enemies seem intelligent, especially as Monolith added chatter to make them seem even smarter. And then one of the expansions had a bunch of open areas and the AI didn't handle those well so the trick didn't work.