I am a veteran FPSer and veteran FO3 player in every sense of the word, but I am finding that this game on very hard/hardcoe-mode is just frustrating with the speed that critters move. Giant rats, night stalkers, etc. are on you before you can take 3 shots at them and then they just maul the bejeezus out of you. Of course it doesn't help that I am trying to use very underpowered energy weapons, but I just find myself dying every single time to critters that come in packs of 2 or more. There's no way to avoid them, and it takes nearly a full clip from the plasma pistol or RCW to take critters like this down.

Am I just doing something wrong?

Edit: I just tried turning down the difficulty to hard and wow, it's MUCH easier to kill critters. On very hard difficulty, even simple critters have way, WAY too much hp. Unbelievable.