The editors at Joystick Division bring us a list of "Five Things We Learned From Fallout" (the original), including how a big combat-heavy finale is far from a necessity:
'‹Fallout subverts conventional RPG standards in several senses. Instead of the typical sword, shield and spells, you have machineguns and grenades. Instead of orcs and goblins, you face anarchists and irradiated scorpions. But maybe the biggest departure from the norms of past videogames is that Fallout doesn't have a mandatory final boss battle. And then Planescape: Torment took that approach even further.
That's right. It's in there, if you want to do it. And it's as tough and intense as any final boss battle you'll ever play. But if you don't feel like taking on a twin-gatling-gun-wielding mutant-goo psychopath, you can do a couple things (spoiler alert!). You can:
A.) Talk him down. Convince him of his folly. That's right, you can actually use diplomacy to prevent the final boss battle in this game.
Or you can:
B.) Just walk past his lair and nuke the entire fucking base. Boom. Goodbye.
Imagine if Mario got to the final stage and encountered his arch-nemesis Bowser, and instead of fighting just reasoned with him until Bowser agreed he had a point and gave up the princess? Or what if Link from Zelda: a Link to the Past was transported to the Dark World, but instead of freeing maidens from crystals and engaging in a final confrontation with Gannon, just hooked up a nuke and blew the entire place to hell?
Sound crazy? Sure. But that type of crazy is what makes Fallout a classic.