It's true I killed a Deathclaw in Fallout 3 and lived to tell about it. However, there's something else; I was playing on normal mode at the time.
A complaint about Fallout 3 I've read is that the game is too easy on the lower difficulty levels. On my second playthrough, this seemed to be the case. I resolved that; now I'm playing on very hard, the highest difficulty level.
At first, it didn't seem that hard, "Oh, I have to shoot Raiders and Feral Ghouls a little more, so what?" But those are generally weak enemies. A baddie's toughness goes up exponentially in the difficulty scale. Namely, a weak enemy won't be much stronger on very hard. A strong enemy? Oh shit.
Then, after changing to very hard,I got killed by Super Mutants. Actually, I didn't just die, I got brutally gibbed, or, as they say on the intarwebz, "gang raped." Oh geeze, Super Mutants are tough on very hard! I didn't switch back to normal, though. I just have to adopt different tactics now.
Here's something you should be thankful for; you cannot become addicted to stimpaks, because you will need them on very hard mode. I'm now tempted to start all over again, but this time, play on very hard from the start, but I want to try to find every location and attempt every sidequest on my current playthrough before starting anew.
Also, I am aware that there is DLC for Fallout 3. Heck, I bought my copy when the newest DLC package came out, but I am avoiding them, because they supposedly are very buggy. I'll just play Fallout 3 as is.
Until Fallout: Las Vegas comes out. Viva, Las Vegas! Viva . . .