- First-person action RPG with the same engine as Fallout 3 (sorry, Van Buren fans).
- Set in the Mojave wastelands. Vegas didn't get many nukes. More intact buildings, as well as desert vegetation. Vegas itself is mostly intact.
- You don't play a Vault Dweller (or descendant of one) but a courier, left for dead and saved by a friendly robot.
- The overarching story is a struggle between the locals, Caesar's Legion (a faction of slavers from the east) and the New Californian Republic. Vegas itself is mostly intact. Both karma and reputation are tracked. If I'm reading it right there's separate reputations for each of the settlements, as in 1 and 2.
- All dialogue options are shown to all players, regardless of whether you have the stats to succeed or not, though there's no punishment for failure.
- Bartering is not just lower prices but negotiating for better rewards.
- VATS returns, and melee weapons have special moves in it. The golf club has "Fore!", which is a shot to the golf balls (so to speak) that knocks the opponent down. Weapons also now have knock-back upon death, with shotguns sending mans flying.
- Super Mutants return, but in two varieties - the smarter ones from Fallout 1, and the idiot ones from Fallout 3. On at least one occasion you can convince them to fight amongst themselves.
- New weapons include what appears to be an M4 and a grenade machinegun.
- Followers can be managed through a context-sensitive menu, with orders like "follow", "stay" or "attack".
- Hardcore Mode! In this mode, Stimpacks heal over time (as opposed to instantly), combat is tougher, ammo has weight and you can suffer dehydration, so keep some water on you
