One of the best games you'll ever play. There is nothing else like it.
Every time I play through this game I find out new things I didn't know about. Little things in this game matter. You'll expect typical "get quest, do quest, get xp". What you'll get is an extremely deep overarching goal/story with a truly 100% open world to figure it all out. From very early on in the game you can just walk right out into the wild... though you'll be beaten to death by bandits very quickly. However, if somehow you survive, the world is open to you if you have the skill to reach it.
What you do will change the game world. For example, if you were to escort a merchant to a new place they want to set up shop and they die while you're transporting them, that merchant will remain dead forever. If instead you make it to your destination, that merchant will set up shop and sell you items you can't normally find anywhere else. Doing one quest may cancel the ability to do another. You're choices make a difference on how things end up.
There are so many items in this game you'll probably personally never see them all unless you cheat and look online. Having the best/highest stat gear is an option, but if you actually read the description on items you'll find that often hidden under the hood is a magical property that makes it better than you thought. For example a shield might have lower stats but when you read, you'll see that it also makes it's wielder stronger against all beasts. This is truly one game that the deeper you look, the more you find.
The combat is perfect. There are so many different ways to battle and all of them feel exactly like you want them to, the controls are the best I've every come across. All enemies have hidden weaknesses that you can discover and teach to pawns (npc's in your party). For example, goblins hate fire and ice. If you use either they will frantically flail around in a panic. Wolves fur is flammable, exactly what you'd expect fur to be. If fire is used when attacking (i.e. flame enchanted sword) you'll catch them on fire and they will roll around trying to put it out. Even the massive beasts have weakness and they are not all elemental. Some enemy's become weaker when you cut off their tails. I'll let you discover the rest for yourself.
In this game, exploring is at the very heart of the experience. In most games, looking behind that rock is pointless, there wont be anything there and after you've checked behind enough rocks, you stop bothering. In Dragons Dogma, looking behind that rock will frequently hold a chest, raw ingredients you can harvest and craft with or a path you didn't expect was there. There are hundreds of secrets in the game. Looking over a cliff side may unveil a hidden path down the rocks into a secret cave with loot inside. I'm not exaggerating either, that cliffside cave is an actual place, have fun finding it.
The time you adventure plays a huge part in what you'll encounter in both villages and the wild. With a day/night cycle, as you would expect, it is much more dangerous at night. With only your lanterns for light, a gaggle of harpies swarming over head is much harder to deal with. Night will also bring out many more enemies and different types than usual so you'll have to be more careful if you're out after dark.
I can't praise this game enough. If you're skeptical just watch some game-play videos to get a feel of what to expect. I can say this, everyone I know who has actually played this game praises it just like I do. I don't know anyone who has played it that doesn't like the game. It's worth every penny.
I'm currently playing through this time as a Mage summoning massive walls of fire and spires of ice as well as healing my party and warding off status effects. I'm having a blast.
This game is 10 years old and it's still my favorite game.