This is a pretty sweet and free (at the moment) 2D Side-scrolling MMO.
It's a pretty in-depth game for a Side-scrolling MMO (Classes, Skill Tree, Quests, Levels, Tons of areas/monsters). If you liked Zelda2 on NES, castlevanias, wonderboy, MMOs then you should find this pretty fun. Wonder King
If you'd like playing with a controller get the program JoytoKey. You can use it to map keyboard keys to controller buttons for games that don't support a controller.