MapleStory

This game is still set around the old style of grinding, meaning that past level 100 you'll be spending literally hours clicking the same button and standing in the same spot, killing the same creatures. You also lose exp when you die, meaning that just a simple lapse in judgement can lose you a good part of a level. The game is advertised as free, however to buy any of the "cute" clothes or level faster you'll need to pay real money. On the plus side this 2d game is very cute and the adorable chibi characters are great for younger players.