A few minor flaws can't stop this game from being essentially the best role-playing game ever created.
On the gameplay side, Oblivion contains some frequent loading screens. The length of the load is anywhere from a handful of seconds to a couple of minutes depending on where you're going: Walking through doors from outside to inside or vice versa is usually pretty quick, especially in towns. Entering larger indoor locations like dungeons can take a bit longer and the fast travel feature that lets you move from your current location to any other previously visited (or major) destination can be the longest, especially if you're traveling long distances across the game's map.
Also, Oblivion can be--despite the overall flood of available information--oddly obtuse about certain elements or occurrances. For example, you get a combined Armor Rating stat that adjusts based on what kinds of armor you're wearing and how effective that armor is, but there is no corresponding offensive statistic other than the currently wielded weapon's base attack power. For stat-hounds it can be a tad annoying to never know exactly how much damage your attacks are doing; the game's meter-based opponent life gauge that appears over your aiming reticule is more of a vague health indicator than a precise representation of their current HP, especially when it gets low. Sometimes the meter will appear to stay unchanged through two or three hits just before they die, which can be a mild problem when trying to decide whom to target with your last fireball for maximum effect. Even a toggleable option to show the actual amout of damage delivered (and perhaps switch from a meter to a numeric value in the HUD) would be welcome. The game is also good about inflicting various status adjustments on you during the course of battle which are indicated by a relatively quickly scrolling message in the upper left of the screen (something you may not always have your eye riveted to, especially in the heat of battle) but the effects carry on after the fight is through without much in the way of indication as to what may be wrong so it can be rectified.
When it comes to game design decisions, the primary issue is that the developer's stated intentions of giving players a really freeform world to experience at their discretion leads to two small concerns: One is that the game is really overwhelming at the beginning. Once you leave the tutorial dungeon the game leaves it entirely in your hands to determine what to do. Stepping foot in the closest city (the capital Imperial City) reveals a town that is larger than players of more typical Japanese-style console RPGs could probably imagine. Spread across five districts, each district holds dozens of individual buildings and a large number of NPCs to interact with, which makes just wandering through one district of the first town likely to take a couple of hours. And in an effort to ensure that no parts of the game are beyond your capability no matter when you try to experience them, Oblivion uses a system that more or less levels up the world along with you. For the most part this works quite well at keeping the challenge consistent, but it does kind of limit the desire to level up when all that will mean is encountering more powerful foes.
As for presentation, the game suffers from a bit of choppiness in places and there is some noticeable pop-in, especially if you travel across open country and you can see the detail textures jump in over the long-distance textures. This is even more pronounced when traveling quickly, such as on horseback. The game features full voice acting for dialogue, too, but with what seems like hundreds of hours of dialogue the designers chose to recycle both script components (ie many NPCs say the same things) and also voices. There is a reasonable variety of voices to go around, but with so many NPCs they all get reused quite a bit. The oddest aspect of this is that some characters will switch voices from time to time depending on what line of dialogue they are to deliver, all of which can really kind of break the spell of the game.
All that said, the only real important thing you need to take from it is that none of these problems are severe enough to ruin or really even hamper the game. Since it is entirely possible to drop 100+ hours in the game without even realizing it, most of the problems aren't even all that noticeable until you've played the game for days on end. And even with *that*, most issues are really comparatively minor. The biggest of the gripes would probably be the loading times and the sense of being overwhelmed, but the loading times are either preferable to traveling by foot long distances (which can be both dangerous and therefore a drain on resources or remarkably time consuming--this is a massive game world) or worth the trade off for the game's terrific visuals. As for the sense of option-paralysis, it fades quickly and can be somewhat managed once you realize that practically every aspect of the game is completely optional.
No matter what else the game does, it should be noteworthy if for no other reason than that it actually allows players to engage in role-playing. From the ludicrously deep character creation system through the open-ended quest setup and the huge variety of activities to engage in, you can choose to play the way you want to. Feel like being the quintessential rogue and stay deep in the shadows, striking hard and fast and then disappearing again? No sweat. Want to be a smooth-talking alchemist who relies on her massive stock of potions to accomplish her task? That's cool. Or would you prefer to be a combat mage wielding a heavy axe and a series of powerful lightning spells? It's not a problem in Oblivion.
But Oblivion shines because it makes any way you want to play the game just as fun. All of the secondary activities are well-designed and enjoyable right down to the persuasion/speechcraft minigame and the lockpicking activity. The game does push you a little to diversify but only if you want to try to experience as much of the game as possible with a single character. It is just as fun if not more so to create several avatars each suited to a different purpose. With six lengthy quests built in (each of which holds several of the game's Achievements) and probably more freeform dungeons, caves, mines, ruins and outskirt settlements plus hours and hours worth of side quests, there is never a lack of things to do.
The game's controls are tight and responsive and the menu systems are well designed to easily access the information you need. The only minor beef is the hotkey system which uses eight points on the D-pad, but eight never seems like enough and the diagonal keys can be frustratingly difficult to access in the heat of battle. Otherwise there is little reason to choose the PC version over the 360 if given the option, unless you're a big fan of user-created content (to date there hasn't been any offered via XBox Live, although all the official updates are available to download from the Marketplace).
The visuals are, as mentioned, phenomenal and the audio is superb with a suitable and stirring score that mercifully doesn't get old even after days of play. The voice acting is all top quality and the sound effects are appropriately authentic. Other than the recycling thing which is only really jarring in the few instances where it happens in mid-conversation or by chance you run across several people with the same voice in a row.
This is, in short, the best all-around console role-playing game ever made. The value of this game is incredibly high, especially with Bethesda clearly committed to continuing to bring new downloadable content to players. Boasting superb production values, a rich and vibrant game world that feels very real and an open ended format which can appeal to any gamer no matter your usual genre predisposition, there is no minor gripe that isn't utterly dwarfed by the sheer avalanche of reasons to recommend this game. Whether you're a role-playing junkie who has been looking for a game like this since you started playing or a sandbox game lover who enjoys experiencing alternate worlds or just a gaming everyman who appreciates top quality games of all types, you owe it to yourself to experience this game.