Fallout 3 was fun, gross and immersive all in one.
There were a couple hiccups though, mostly with the level capping. I seriously hate level capping, and at lvl20? Jeez. I wasn't even half way done with the game before I was capped. It feels like crap killing stuff and doing quests without being rewarded for it. The most fun you get in these types of game is character building. That's the only reason I played through Oblivion. There was no stop to the character building, but there was in this game.
----------Battle System----------
Fallout 3 is an action RPG. There are no character classes, but at the start of the game you get to add points to a few attributes that give your character his stance on strength, intelligence and so on. When you gain levels, you get points to add to specialized skills, like the ability to repair items or to unlock safes. The higher these skills, the better they become, obviously. You also get one bonus ability with each level too. These abilities are specific in their qualities. For example, one of them might boost your strength but only at night.
You gain experience for each kill or quest finished. I prefer this method over Oblivion's leveling system. However, you get level capped at 20, which freaking sucks. I barely scratched the surface of the game before I got capped off, and that annoyed me so much I quit doing all sidequests and just finished with the game. Why would they level cap you for one, and why would they do it at such a low level? I think it's because of the stupid downloadable content levels. I don't like feeling penalized because they want to sell you extra content. For a game that's all about freedom and choice, they sure do strip that away from you in terms of character building.
----------Characters / Story----------
You make your own character, not that it matters what he/she ends up looking like, because you won't ever see him/her. However, you're a person stuck inside of a lively vault, away from the impurities of the devastated world above them. Your dad is a scientist working on a way to make a water purifier. He escapes the vault without permission, and you go on a quest to find him.
----------Graphics----------
The graphics are really awesome. Maybe it's because of the source material, or whatever, but there seems to be better art in this game compared to Oblivion. Oblivion was just boring stock fantasy. Fallout 3 is creative, disgusting, scifi. I don't even like Scifi, but I had a ton of fun living in this world. Granted, this wasn't Bethesda original creation, but they did a great job with the material that was given to them.
The world looks great, the enemies look gross, the gore is just gruesome. The character animations are still rather stiff, and I still hate dialog scenes in this game (why can't western developers figure out a good way to show off dialog scenes?). Otherwise, I love the graphics and the style.
----------Sound----------
Voice acting is hit and miss. Some actors are really super generic, especially the non-important ones. They're either poorly acted or just terrible sounding. There are some shining moments in the voice acting, but it's nothing to special compared to other games.
The music creates a nice atmosphere though. There are radio stations you can listen to in the game, some depending on what area of the world you're in. However, I found those distracting, and rarely listened to them.
----------World Map----------
Fallout 3 is an open-ended RPG, and the world reflects on that. You can pretty much do whatever you want once you leave the vault. There isn't much in your way into exploring the world.
The world map isn't much different than Oblivion though. You can fast travel, exactly like Oblivion. You can rest and speed up time if you want too. Although, you don't heal up like you do in Oblivion though. The only true difference is the bigger variety of dungeons and even landscapes.
----------Time to Complete Game---------
46:36:33
The game ends and that's that. There are multiple endings if you choose to do them. I wasn't to thrilled with the one I got, since it was just a short epilogue ending, so why bother with the rest if they're just the same? Either way, if you want, you can go back to your old save states and do more quests. Otherwise, there are no rewards that I know of for beating the game, other than achievements. Woo.