Well game play is well action combat based like if you don't aim on the monster u miss you have a few classes, Archer,Warrior,Lancer,Sorcerer,Berserker,Mystic,Pr iest,Slayer.
Here are some class info http://tera.enmasse.com/game-guide/classes
Quest are plenty but you have a dead zone somewhere around level 30+ if they have not fixed that yet at least not in EU last I played month ago.
PVP im not 100% on more than battlegrounds wich is fun team vs team pvp.
Well im not great at this but here some info I know itīs from US but mostly the same as EU info expect EU is alwyas like way way behind US and Korean version.
http://tera.enmasse.com/game-guide






