1. Feral ghoul reavers- Even at lv 30 they are near unstoppable and easily outrun you (my most hated enemy). Recommended weapons and tactics= firing retreat with a tri beam or plasma rifle. nukes are preferred but as they are so fast you may die in the presses of using one.
2. Giant rad scorpions.- They always seem to hunt in 2's, are very fast, can kill you in about 4 hits wearing power armor and can take a hell of a beating.Recommended weapons and tactics= run and get to high ground then use any small arms to take em down, they will continue trying to attack you without success, if your not near any rocks, jump on a car, its just high enough.
3 Overlords.- fast, very powerful, more so than behemoths and can kill you in 2-3 hits, carry super sledges or tri-beam laser rifles. Takes allot of small arms fire or a mini nuke or 2 to take down. Recommended weapons and tactics= keep moving, don't try to run just keep moving to avoid his attacks whilst repeatedly blasting him with your strongest weapons. nuke them from a distance. If you have bottlecap mines place em down and they will reduce his health to the point where a few good shots will finish him.
4, sentry bots.- Not much of a threat if your wearing good armor but they are a pain to kill. Recommended weapons and tactics= keep moving and shooting, plasma nades and mines are very effective.
Cheers-
Ronin82