The first is text-description. You get little atmosphere-building text descriptions of areas. I haven't seen this in ages and it adds so much.
Everything is interactive to some degree. See a shelf? You can rummage through it. A bin, box, crate? Same thing, it's not just a graphic detail, it's an item in the world which you can interact with. Signs all say something, physical objects have text descriptions which serve as either setting detail or as clues. You can talk to anyone and have a conversation, and sometimes it surprsingly contains something useful.
The game doesn't hold your hand and point you in all the proper directions, or lay useful items at your feet, you are actually require to strategise, note things down, plan and explore.
What it boils down to is that Fallout 2, like the RPGs that came before it and very few since, cannot be rushed through with nary a second thought or glance around the world. Most RPGs these days you just run through, with map pointers showing you exactly where to go and that's that. What made RPGs the games they were was the time-taking, the things that were there as direct translations from what you'd do in a PnP game. Anyone who played tabletop RPGs knows how it is to search every nook and cranny, every container or room that the DM tells you is there, since if it's there it *must* be important (

RPGs these days don't have these things, which is sad. So I guess my point in posting this here is that I hope Eschalon can recapture some of this, that the dev team keeps these old hallmarks in mind and doesn't succumb to the modern perspective of cRPG making.