You know what? Instead of blowing up Megaton to enjoy the nuclear explosion. I found some satellite tower which allows you to bombard rain of Nuclear, however... still figuring how to coordinate it hehe... Will post screenshot later.

Here goes...

Ladies and gentlemen, may I present you... *drums*

Sounds like you have a hard time with the combat system it's quite fun for many of us ex-FO1/2 players. Here are some of my observations why you might be struggling, I'm not a pro player but I found these things helpful.

[Perception] Yes you should get Sniper perk. Perception 3 is the main reason you are suffering because you can't get the perks, and you can't spot the enemy until they are pumping bullets into your backside.

[Long Range] VATS sniping, like you said, is not very good after mid range. You have to adjust your style depending on range. If the mutant is really far away, you turn on sneak (even tho with low skill, they won't detect you since too far). You just manual snipe using the scope. It's basically a free headshot if you hit them, and sometimes the AI just runs around confused so you can hit a few more.

[I'm being shot at!] If the mutant is shooting at you from midrange, terus run behind a wall out of their line of fire. Don't stand in the open and trade shots. Now you can play chicken-style, means you pop out of wall, open VATS with a rifle and unload, then hide behind wall again to recharge AP. Repeat.

[He's running at me!] If there is a shotgun or melee mutant, confirm he will charge onto you. Basically use a shotgun (or a geng SMG). Again hide behind a wall, wait for him to turn the corner, and then use VAT to pump shotgun into his head.

I use the super duper mart's containers to store stuff in one of my newer games... I wanted to complete some quests before blowing up megaton... but also didn't feel like selling everything. Nothing missing yet. I doubt it will. But in one of my more progressed games entire context-sensitive npc's vanish through no fault of my own or anything that happened while I was around. (Lucy West and Walter the Purifier Mechanic...)

This... is probably a bug, though.

Yes, apparently NPCs frequently fall to their deaths around Megaton. I don't know if that game mechanic is an artifact of a severely twisted sense of humor or a pathing bug. A modded fix for that will be number two on my wish list when and if a construction set is released.

how to get the dog?

Hahahahaha that's f***ed up but hilarious.

Fallout 3 is full of funny moments. Using VATS in melee can lead to some really odd situations especially when you engage it from a distance and teleport towards the enemy. One time I queued up a string of melee attacks on a raider only to watch in horror as Dogmeat decided to leap in slow motion right in front of my flaming shishkebab. I critical hit him too, poor guy. Too bad I lost him later in the BOS super mutant behemoth fight.

I finished Daggerfall, Morrowind, Fallout 1, Fallout 2, Jagged Alliance, X-Com myself. Yes, Fallout 3 is a very very good game

Back to the game, I discovered something hilarious. If you ever been to Big Town, you will get a mission to rescue two guys from mutants and then teach the village how to survive. The funny thing is, if you gave the two guys grenades earlier, they will accidentally grenade the whole village to death during the small guns training.

I like the world and environment design in FO3, but bethesda sure doesn't know how to design character figures, look at all the NPC and monster almost all has the same face and same body size, they just add in some little clothing texture....and frankly speaking it's indeed ugly too