Runescape is, I believe, written entirely out of Java. the game has some 3D graphics, but they're very poor in quality. Half of all the graphics in the game are 2D, further damaging the quality. I find that the servers are slow, and the atmosphere is very 'While you are screaming for help, I'll just stand back here waiting for you to die so I can nab your loot'. Runescape has a very confusing setup, being entirely mouse-based. This makes you navigate endless menus to do the most simple of tasks. Fighting is boring, at most, because the only choices you have are 'fighting strategies'. I put those in quotes because they aren't even a strategy. They simply add status points during the combat.

In short, stay away. Stay far away.