What is the Appeal to Super Smash Bros??

[Super_Boom]

Yeah! I also hate fun! Let's all play Cawadooty.

Seriously though, the appeal is largely in how easy it is to pick up and have fun with friends. It's a game that's easy to be good at, but very difficult to truly master, so it draws in all sorts of fans. The games also have a lot of replay value, so even though it's meant to be played multiplayer, playing through all the single player modes and unlocking all the levels/characters is a very satisfying experience.

Of course, being a Nintendo fan only makes it more fun, as the central theme is Nintendo's huge IP legacy. It's far away from being a requirement, however, as should be evident by most of the comments in this thread.