RE: Hard Battle
While the final battles are pretty messy, some of the random encounters can really suck depending on your level. I kept running into the "last ranks of the masters army" when it was just me and sulik. Even the battle to take vault 15 was a bit of a bother at the earlier levels, because everyone and their mother comes running up and surrounds you in seconds.
Probably the worst battle in the game tho is turning the robots on in the lower levels of the Army Depot. I have gone back in there with charactors that could beat the game, and still gone down. Its the F---ing missle robots, they plague me so. I have never had the forsight to build a charactor with a good throwing arm, so pulse granades never work out... its evil.