I own all the games in the Super Smash Bros series, I think the thing I liked most about them was that I've always been a fighting game fan but most of my friends weren't so its a pain to get them to play and enjoy fighting games. Super Smash however was a game that anyone could easily step into and not only have fun but feel like they were competing (even if you were really just toying with them). The ability to 2 on 2 co-op against computers was also very cool and something most other fighting games lack.
Ironically years after playing melee I made some friends who were OBSESSIVE about the smash games. I mean years after its release they were still spending hours every day training to get better and holding weekly tournaments for money. For once I was the one being toyed with... but it was awesome to finally have a challenge and I did still take my share of wins in 4 player free-for-alls and if I was lucky even occasionally in 1 on 1s.
When Brawl first came out I was playing it non-stop but now adays its pretty much become relegated to the game I sometimes play when I have friends over. I have played it online a little bit but the online features are definitely lacking and didn't really give me a strong incentive to keep playing and improving. I also don't see my SSB obsessive friends much anymore (darn you World of Warcraft) so with out them to play I have even less reason to train, but on the bright side my rusting skills give my more casual friends a better chance when we play.
The bunnies of Lavato have special abilities, like 'Action Skill: Make Carrot Disappear.'