One thing about any vid game that i like or get annoyed by is how villians/monsters/etc progress as my PC gains levels. In Oblivion IV, getting stronger meant very little as everyone in the world progresses as my PC did. In Fallout, some areas are tough, some are safe, some become safe as my PC gets tougher. I prefer that approach as it mimics my game world.
This is exactly the style of my RM campaign: I detest level-dependent encounters. Why should bandits automatically get more powerful when the PCs level up? Why should a big, old dragon be any easier when the PCs meet him and decide to attack, even though they are small fish?
If the players decide to confront an NPC, an animal, creature or monster that is way above their head, I offer possibilities to get away or around, I ask them if they are sure that they want to attack, but that is all I do. If they really want to test their luck and limits, who am I to stop them?
By the way, when all the PCs were 1st level characters, they killed a level 15 mountain troll in less than four rounds. At first I was angry, because I thought that was suicide, then I was flabbergasted as they grinded the troll into tiny bits in such an amazing little time. And then I laughed, beingt amazed at the creativity and luck of those players.
Back to topic: perhaps the PCs are the most important personas in the campaign, but that does not mean that the world changes according to their prowess. In my opinion at least. I always want to present a rich and colorful world that reacts to the PCs, is changed and influenced by them and their actions, but is definitely much larger than they.
I do not know if
Fallout had a big impact on my mindset, but it definitely is very similar to that in its core.