(First post, BTW. Been lurking for awhile now and finally got around to joining
)
In Fallout, definitely the Glow: all the radiation messages, the overall eerie feel, and finding out about FEV for the first time
. I also really liked the Vats, and finding out I could become a Super Mutant. It'd be nice if there was a way you could be one without joining the master.
Fallout 2, I loved the Sierra Army Depot. It was one of the best parts of the game for me, finding out that the base still somehow was functioning, the supercomputer, being able to build your own brain bot, reviving the general before watching him melt, and the whole thing with extracting the Ebola/Smallpox/Anthrax virus from storage. The first time I went through, I messed something up and the moment I got out of the base, Skynet left my party and attacked me
. Also, it was nice being able to have an actual conversation with Marcus from Broken Hills instead of the usual 'Me take you to boss-man'
. Re-exploring the Military Base, and being able to compare to Fallout was fun, and I liked the wide variety of things you could do withthe Gecko Power Plant. Loved how the sign above the entrance read 'Poseidon Oil'