2 hours of gameplay experience as below (SPOILER ALERT) (after borrowing it from a rich ******* who orders everything online):
1. Skills. Gone are first aid and doctor, replace by Medicine. So you can now heal crippled arm/leg with STIMPACK. 
Speech is pretty much useless since the game's dialog is uninspiring and lack of creativity to read. Perhaps the most shocking skill is repair, which in previous FO game only works on certain place. In FO3 you have to maintain your weapon and armor, like System Shock series.

2. Perks. Judging from the selection of choice, 60% of the perks are gear toward for a combat-type character.   

3. Encounter. Imagine the shock of finding missile launcher at level 3...

4. Unkillable NPC! They DO exist in the game.

5. Annoying Intro. Seriously, Bethesda's trademark of lengthy character creation is a pain-in-the-arse but the combat is twitch based. Ironically, in previous Fallout game all you have is a brown paper (simulated) loaded with character details and customization with short intro but complex combat mechanic.

6. Spoon fed everything. In FO3 you are flooded with many information when trying to do something. Say when lockpicking a door, the game will tell you you need x amount of lockpick skill percentage to do it. Rather than letting you try it straight away. Todd and his gang should take a class of Design 101.

7. VAT is a joke. For the action sequence. Once you pick your target, the camera switch to action shot demonstrating the effect. It's fun to watch first time but after that it's getting annoying. When encounter an enemy I just run backward and shoot, just like every FPS game.
During my attempt of escaping Vault 101, I killed every NPC in there except for one(Unkillable NPC!) with ease and the game is set in VERY HARD mode.   

8. FO3 should be rename to Fallout Tactics 2. There are numerous edible items in the game. From bloatfly meat to Squirrel meat!
Fallout 3 is Oblivion with guns

Hoong, you're giving FO3 too much expectation. Fallout 3 requires COMPLETE suspense of logic. You're not supposed to think when playing the game. It's better to play the game as a moron because if you put in any intelligence into it you'll find an infinite array of questions.

Happened to me too... I told the Sheriff about the deal to blow Megaton, and watched the confrontation in the saloon. THen when the bad guy wants to shoot the sheriff I went into VATS and capped him. After that, the sheriff was nowhere to be seen, so I walked outside... only to have the Sheriff drop from the sky, crash in front of me and died.

Bugs? No, that's just how Beth make games. It's their idea of humor.

TOO MANY.. 

i'm the type that clears all the quests in an area before continuing. yes it's been a long one for me. those brats in that lamp caverns sure are annoying. and i thought the ghouls were bad..