Quests are called missions, you form a party in an outpost zone (either formed of other players or NPCs) and then you enter the mission and get your own instance of that zone. You get diverse objectives for each missions, and a secondary objective which are usually hard to find. In the first mission in Kryta for example, you eventually get to a town under attack by warlocks, if you save enough villagers and a specific NPC from the attack you are asked to deliver some item (don't remember what) to a specific place, and you get bonus xp for doing this. Later in the mission you have to protect someone from a constant attack of undead, which is lots of fun.
Character creation is pretty basic, you start by getting a name and last name, then you choose two professions (primary, secondary) and you can modify your characters appearance (height, gender, face, hairstyle, haircolor). As you progress through the game you earn ability points which you can use to upgrade abilities, such as swordsmanship (warrior) healing spells (monk) blood magic (Necro). You also get skill points which are used to buy some skills from NPCs in town, you are limited to 200 or so ability points for a character (which lets you specialize on about 3 different abilities) but you can have as many skill points as you want, though it takes a lot of xp to get another skill point when you're past level 20. Oh and level 20 is the max, you can have up to 150 skills total, but you can only bring 8 for a mission.
Combat is the best part of the game, it's very strategic and it asks you to think hard before a mission (to get the good skills) and think fast during a battle. Even when playing a Warrior you almost always have something to do, and not everything is good. For example, a warrior has the bull's strike ability, this skill works only against running opponents, it does more damage and knocks them down. But if you use it and the ennemy stops running it's just like a normal attack except that you used energy for it. Monks have spells that heal a character each time he's hit (usually around 20 or so hp), if the monk is good enough in healing it can make a warrior invincible for a moment, but if another monk casts scourge healing on that warrior, each time he gets healed he can take up to 70 damage. If no one does that it's a good idea to switch targets till the spell ends, or simply remove that spell from him (if you have a skill that does that). I have often seen players who didnt change targets, and half the group was fighting an invincible warrior while the elementalists killed them. So unlike most action RPGs the combat is very tactical.
The game is most easily compared to diablo 2, though I must say it'll probably end up much better. It's an online action RPG with tactical combat and great pvp, or CORPG (competitive online role-playing game) as Anet would say.
Hope that answers your questions!
